1861213925 has 12 divisors (see below), whose sum is σ = 2308545696. Its totient is φ = 1488558000.

The previous prime is 1861213853. The next prime is 1861213927. The reversal of 1861213925 is 5293121681.

It is a happy number.

It is not a de Polignac number, because 1861213925 - 2¹² = 1861209829 is a prime.

It is a super-3 number, since 3×1861213925³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861213927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 108272 + ... + 124278.

It is an arithmetic number, because the mean of its divisors is an integer number (192378808).

Almost surely, 2^1861213925 is an apocalyptic number.

It is an amenable number.

1861213925 is a deficient number, since it is larger than the sum of its proper divisors (447331771).

1861213925 is a wasteful number, since it uses less digits than its factorization.

1861213925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20668 (or 20663 counting only the distinct ones).

The product of its digits is 25920, while the sum is 38.

The square root of 1861213925 is about 43141.7886161434. The cubic root of 1861213925 is about 1230.0764323359.

The spelling of 1861213925 in words is "one billion, eight hundred sixty-one million, two hundred thirteen thousand, nine hundred twenty-five".