25250021391 has 24 divisors (see below), whose sum is σ = 40866056064. Its totient is φ = 13801252080.

The previous prime is 25250021383. The next prime is 25250021431. The reversal of 25250021391 is 19312005252.

It is not a de Polignac number, because 25250021391 - 2³ = 25250021383 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25250021371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3730725 + ... + 3737486.

It is an arithmetic number, because the mean of its divisors is an integer number (1702752336).

Almost surely, 2^25250021391 is an apocalyptic number.

25250021391 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

25250021391 is a deficient number, since it is larger than the sum of its proper divisors (15616034673).

25250021391 is a wasteful number, since it uses less digits than its factorization.

25250021391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7468251 (or 7468244 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 30.

The spelling of 25250021391 in words is "twenty-five billion, two hundred fifty million, twenty-one thousand, three hundred ninety-one".