21242504451 has 24 divisors (see below), whose sum is σ = 33089017104. Its totient is φ = 12086457600.

The previous prime is 21242504441. The next prime is 21242504461. The reversal of 21242504451 is 15440524212.

It is an interprime number because it is at equal distance from previous prime (21242504441) and next prime (21242504461).

It is not a de Polignac number, because 21242504451 - 2⁷ = 21242504323 is a prime.

It is a super-2 number, since 2×21242504451² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21242504441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 275850 + ... + 344351.

It is an arithmetic number, because the mean of its divisors is an integer number (1378709046).

Almost surely, 2^21242504451 is an apocalyptic number.

21242504451 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21242504451 is a deficient number, since it is larger than the sum of its proper divisors (11846512653).

21242504451 is a wasteful number, since it uses less digits than its factorization.

21242504451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 620451 (or 620444 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 30.

The spelling of 21242504451 in words is "twenty-one billion, two hundred forty-two million, five hundred four thousand, four hundred fifty-one".