21504255200421 has 12 divisors (see below), whose sum is σ = 33353538678432. Its totient is φ = 12288145828728.

The previous prime is 21504255200387. The next prime is 21504255200443. The reversal of 21504255200421 is 12400255240512.

It is not a de Polignac number, because 21504255200421 - 2¹¹ = 21504255198373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21504215200421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 73143725025 + ... + 73143725318.

It is an arithmetic number, because the mean of its divisors is an integer number (2779461556536).

Almost surely, 2^{21504255200421} is an apocalyptic number.

21504255200421 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21504255200421 is a deficient number, since it is larger than the sum of its proper divisors (11849283478011).

21504255200421 is a wasteful number, since it uses less digits than its factorization.

21504255200421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146287450360 (or 146287450353 counting only the distinct ones).

The product of its (nonzero) digits is 32000, while the sum is 33.

The spelling of 21504255200421 in words is "twenty-one trillion, five hundred four billion, two hundred fifty-five million, two hundred thousand, four hundred twenty-one".