21500442321025 has 12 divisors (see below), whose sum is σ = 26747390665072. Its totient is φ = 17144326639440.

The previous prime is 21500442321019. The next prime is 21500442321047. The reversal of 21500442321025 is 52012324400512.

It is a happy number.

It is not a de Polignac number, because 21500442321025 - 2¹⁵ = 21500442288257 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1400672607 + ... + 1400687956.

Almost surely, 2^{21500442321025} is an apocalyptic number.

21500442321025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21500442321025 is a deficient number, since it is larger than the sum of its proper divisors (5246948344047).

21500442321025 is a wasteful number, since it uses less digits than its factorization.

21500442321025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2801360880 (or 2801360875 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 31.

Adding to 21500442321025 its reverse (52012324400512), we get a palindrome (73512766721537).

The spelling of 21500442321025 in words is "twenty-one trillion, five hundred billion, four hundred forty-two million, three hundred twenty-one thousand, twenty-five".