77640525 has 60 divisors (see below), whose sum is σ = 150160032. Its totient is φ = 39584160.

The previous prime is 77640509. The next prime is 77640529. The reversal of 77640525 is 52504677.

77640525 is a `hidden beast` number, since 7 + 7 + 640 + 5 + 2 + 5 = 666.

It is not a de Polignac number, because 77640525 - 2⁴ = 77640509 is a prime.

It is a super-2 number, since 2×77640525² = 12056102244551250, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 77640525.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77640529) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 45742 + ... + 47408.

Almost surely, 2^77640525 is an apocalyptic number.

77640525 is a gapful number since it is divisible by the number (75) formed by its first and last digit.

It is an amenable number.

77640525 is a deficient number, since it is larger than the sum of its proper divisors (72519507).

77640525 is a wasteful number, since it uses less digits than its factorization.

77640525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1712 (or 1698 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 36.

The square root of 77640525 is about 8811.3860998143. The cubic root of 77640525 is about 426.6084837518.

The spelling of 77640525 in words is "seventy-seven million, six hundred forty thousand, five hundred twenty-five".