21624647493 has 4 divisors (see below), whose sum is σ = 28832863328. Its totient is φ = 14416431660.

The previous prime is 21624647489. The next prime is 21624647519. The reversal of 21624647493 is 39474642612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21624647493 - 2² = 21624647489 is a prime.

It is a super-2 number, since 2×21624647493² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21624637493) 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, 3604107913 + ... + 3604107918.

It is an arithmetic number, because the mean of its divisors is an integer number (7208215832).

Almost surely, 2^21624647493 is an apocalyptic number.

It is an amenable number.

21624647493 is a deficient number, since it is larger than the sum of its proper divisors (7208215835).

21624647493 is an equidigital number, since it uses as much as digits as its factorization.

21624647493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7208215834.

The product of its digits is 1741824, while the sum is 48.

The spelling of 21624647493 in words is "twenty-one billion, six hundred twenty-four million, six hundred forty-seven thousand, four hundred ninety-three".