25657221021 has 24 divisors (see below), whose sum is σ = 35583463872. Its totient is φ = 16443144000.

The previous prime is 25657220983. The next prime is 25657221061. The reversal of 25657221021 is 12012275652.

It is not a de Polignac number, because 25657221021 - 2¹⁰ = 25657219997 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25657221061) 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, 405865 + ... + 464801.

It is an arithmetic number, because the mean of its divisors is an integer number (1482644328).

Almost surely, 2^25657221021 is an apocalyptic number.

It is an amenable number.

25657221021 is a deficient number, since it is larger than the sum of its proper divisors (9926242851).

25657221021 is a wasteful number, since it uses less digits than its factorization.

25657221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59153 (or 59122 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 33.

Adding to 25657221021 its reverse (12012275652), we get a palindrome (37669496673).

The spelling of 25657221021 in words is "twenty-five billion, six hundred fifty-seven million, two hundred twenty-one thousand, twenty-one".