9902725561 has 4 divisors (see below), whose sum is σ = 9904155124. Its totient is φ = 9901296000.

The previous prime is 9902725519. The next prime is 9902725589. The reversal of 9902725561 is 1655272099.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7511515561 + 2391210000 = 86669^2 + 48900^2 .

It is a cyclic number.

It is not a de Polignac number, because 9902725561 - 2⁷ = 9902725433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9902725661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 704340 + ... + 718261.

It is an arithmetic number, because the mean of its divisors is an integer number (2476038781).

Almost surely, 2^9902725561 is an apocalyptic number.

It is an amenable number.

9902725561 is a deficient number, since it is larger than the sum of its proper divisors (1429563).

9902725561 is a wasteful number, since it uses less digits than its factorization.

9902725561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1429562.

The product of its (nonzero) digits is 340200, while the sum is 46.

The square root of 9902725561 is about 99512.4392274654. The cubic root of 9902725561 is about 2147.4262015809.

The spelling of 9902725561 in words is "nine billion, nine hundred two million, seven hundred twenty-five thousand, five hundred sixty-one".