25599620981 has 4 divisors (see below), whose sum is σ = 27926859264. Its totient is φ = 23272382700.

The previous prime is 25599620957. The next prime is 25599620983. The reversal of 25599620981 is 18902699552.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25599620981 is a prime.

It is a super-2 number, since 2×25599620981² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25599620983) 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, 1163619125 + ... + 1163619146.

It is an arithmetic number, because the mean of its divisors is an integer number (6981714816).

Almost surely, 2^25599620981 is an apocalyptic number.

It is an amenable number.

25599620981 is a deficient number, since it is larger than the sum of its proper divisors (2327238283).

25599620981 is a wasteful number, since it uses less digits than its factorization.

25599620981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2327238282.

The product of its (nonzero) digits is 3499200, while the sum is 56.

The spelling of 25599620981 in words is "twenty-five billion, five hundred ninety-nine million, six hundred twenty thousand, nine hundred eighty-one".