25621542442 has 4 divisors (see below), whose sum is σ = 38432313666. Its totient is φ = 12810771220.

The previous prime is 25621542431. The next prime is 25621542449. The reversal of 25621542442 is 24424512652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 15873732081 + 9747810361 = 125991^2 + 98731^2 .

It is not an unprimeable number, because it can be changed into a prime (25621542449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6405385609 + ... + 6405385612.

Almost surely, 2^25621542442 is an apocalyptic number.

25621542442 is a deficient number, since it is larger than the sum of its proper divisors (12810771224).

25621542442 is a wasteful number, since it uses less digits than its factorization.

25621542442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12810771223.

The product of its digits is 153600, while the sum is 37.

The spelling of 25621542442 in words is "twenty-five billion, six hundred twenty-one million, five hundred forty-two thousand, four hundred forty-two".