1861651125 has 48 divisors (see below), whose sum is σ = 3437873712. Its totient is φ = 968640000.

The previous prime is 1861651123. The next prime is 1861651139. The reversal of 1861651125 is 5211561681.

1861651125 is a `hidden beast` number, since 1 + 8 + 616 + 5 + 11 + 25 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 575568081 + 1286083044 = 23991^2 + 35862^2 .

It is not a de Polignac number, because 1861651125 - 2¹ = 1861651123 is a prime.

It is a super-2 number, since 2×1861651125² = 6931489822427531250, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1861651125.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861651123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 25945 + ... + 66305.

It is an arithmetic number, because the mean of its divisors is an integer number (71622369).

Almost surely, 2^1861651125 is an apocalyptic number.

1861651125 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1861651125 is a deficient number, since it is larger than the sum of its proper divisors (1576222587).

1861651125 is a wasteful number, since it uses less digits than its factorization.

1861651125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40423 (or 40410 counting only the distinct ones).

The product of its digits is 14400, while the sum is 36.

The square root of 1861651125 is about 43146.8553315302. The cubic root of 1861651125 is about 1230.1727399671.

The spelling of 1861651125 in words is "one billion, eight hundred sixty-one million, six hundred fifty-one thousand, one hundred twenty-five".