25221211521 has 16 divisors (see below), whose sum is σ = 37950413760. Its totient is φ = 14758493120.

The previous prime is 25221211451. The next prime is 25221211537. The reversal of 25221211521 is 12511212252.

It is a cyclic number.

It is not a de Polignac number, because 25221211521 - 2¹¹ = 25221209473 is a prime.

It is a super-2 number, since 2×25221211521² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 25221211491 and 25221211500.

It is not an unprimeable number, because it can be changed into a prime (25221211571) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13176270 + ... + 13178183.

It is an arithmetic number, because the mean of its divisors is an integer number (2371900860).

Almost surely, 2^25221211521 is an apocalyptic number.

It is an amenable number.

25221211521 is a deficient number, since it is larger than the sum of its proper divisors (12729202239).

25221211521 is a wasteful number, since it uses less digits than its factorization.

25221211521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26354496.

The product of its digits is 800, while the sum is 24.

Adding to 25221211521 its reverse (12511212252), we get a palindrome (37732423773).

The spelling of 25221211521 in words is "twenty-five billion, two hundred twenty-one million, two hundred eleven thousand, five hundred twenty-one".