21365354451 has 16 divisors (see below), whose sum is σ = 32609516544. Its totient is φ = 12188979264.

The previous prime is 21365354431. The next prime is 21365354453. The reversal of 21365354451 is 15445356312.

It is a happy number.

It is not a de Polignac number, because 21365354451 - 2¹⁹ = 21364830163 is a prime.

It is a super-2 number, since 2×21365354451² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21365354453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 811515 + ... + 837428.

It is an arithmetic number, because the mean of its divisors is an integer number (2038094784).

Almost surely, 2^21365354451 is an apocalyptic number.

21365354451 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21365354451 is a deficient number, since it is larger than the sum of its proper divisors (11244162093).

21365354451 is a wasteful number, since it uses less digits than its factorization.

21365354451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1649570.

The product of its digits is 216000, while the sum is 39.

The spelling of 21365354451 in words is "twenty-one billion, three hundred sixty-five million, three hundred fifty-four thousand, four hundred fifty-one".