61521591807 has 24 divisors (see below), whose sum is σ = 95909747024. Its totient is φ = 37776564864.

The previous prime is 61521591641. The next prime is 61521591809. The reversal of 61521591807 is 70819512516.

61521591807 is a `hidden beast` number, since 6 + 1 + 52 + 1 + 591 + 8 + 0 + 7 = 666.

It is not a de Polignac number, because 61521591807 - 2²² = 61517397503 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61521591809) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 521833 + ... + 628770.

Almost surely, 2^61521591807 is an apocalyptic number.

61521591807 is a deficient number, since it is larger than the sum of its proper divisors (34388155217).

61521591807 is a wasteful number, since it uses less digits than its factorization.

61521591807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1151079 (or 1151076 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 45.

The spelling of 61521591807 in words is "sixty-one billion, five hundred twenty-one million, five hundred ninety-one thousand, eight hundred seven".