25905617921 has 8 divisors (see below), whose sum is σ = 26348146944. Its totient is φ = 25463664720.

The previous prime is 25905617917. The next prime is 25905617929. The reversal of 25905617921 is 12971650952.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25905617921 - 2² = 25905617917 is a prime.

It is a super-2 number, since 2×25905617921² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25905617929) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52721 + ... + 233646.

It is an arithmetic number, because the mean of its divisors is an integer number (3293518368).

Almost surely, 2^25905617921 is an apocalyptic number.

It is an amenable number.

25905617921 is a deficient number, since it is larger than the sum of its proper divisors (442529023).

25905617921 is a wasteful number, since it uses less digits than its factorization.

25905617921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287911.

The product of its (nonzero) digits is 340200, while the sum is 47.

The spelling of 25905617921 in words is "twenty-five billion, nine hundred five million, six hundred seventeen thousand, nine hundred twenty-one".