1665251525 has 36 divisors (see below), whose sum is σ = 2406166308. Its totient is φ = 1139927040.

The previous prime is 1665251513. The next prime is 1665251527. The reversal of 1665251525 is 5251525661.

It can be written as a sum of positive squares in 6 ways, for example, as 400240036 + 1265011489 = 20006^2 + 35567^2 .

It is not a de Polignac number, because 1665251525 - 2⁶ = 1665251461 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665251527) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1367717 + ... + 1368933.

It is an arithmetic number, because the mean of its divisors is an integer number (66837953).

Almost surely, 2^1665251525 is an apocalyptic number.

It is an amenable number.

1665251525 is a deficient number, since it is larger than the sum of its proper divisors (740914783).

1665251525 is a wasteful number, since it uses less digits than its factorization.

1665251525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2358 (or 2346 counting only the distinct ones).

The product of its digits is 90000, while the sum is 38.

The square root of 1665251525 is about 40807.4934907794. The cubic root of 1665251525 is about 1185.2954392822.

The spelling of 1665251525 in words is "one billion, six hundred sixty-five million, two hundred fifty-one thousand, five hundred twenty-five".