21502014451 has 4 divisors (see below), whose sum is σ = 21505599952. Its totient is φ = 21498428952.

The previous prime is 21502014433. The next prime is 21502014481. The reversal of 21502014451 is 15441020512.

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

It is a cyclic number.

It is not a de Polignac number, because 21502014451 - 2⁵ = 21502014419 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21502014481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1783740 + ... + 1795753.

It is an arithmetic number, because the mean of its divisors is an integer number (5376399988).

Almost surely, 2^21502014451 is an apocalyptic number.

21502014451 is a deficient number, since it is larger than the sum of its proper divisors (3585501).

21502014451 is an equidigital number, since it uses as much as digits as its factorization.

21502014451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3585500.

The product of its (nonzero) digits is 1600, while the sum is 25.

Adding to 21502014451 its reverse (15441020512), we get a palindrome (36943034963).

The spelling of 21502014451 in words is "twenty-one billion, five hundred two million, fourteen thousand, four hundred fifty-one".