21621517325747 has 4 divisors (see below), whose sum is σ = 21683827174296. Its totient is φ = 21559207477200.

The previous prime is 21621517325711. The next prime is 21621517325839. The reversal of 21621517325747 is 74752371512612.

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 21621517325747 - 2¹⁴ = 21621517309363 is a prime.

It is a super-2 number, since 2×21621517325747² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21621517324747) 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 3 ways as a sum of consecutive naturals, for example, 31154923754 + ... + 31154924447.

It is an arithmetic number, because the mean of its divisors is an integer number (5420956793574).

Almost surely, 2^{21621517325747} is an apocalyptic number.

21621517325747 is a deficient number, since it is larger than the sum of its proper divisors (62309848549).

21621517325747 is an equidigital number, since it uses as much as digits as its factorization.

21621517325747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62309848548.

The product of its digits is 4939200, while the sum is 53.

The spelling of 21621517325747 in words is "twenty-one trillion, six hundred twenty-one billion, five hundred seventeen million, three hundred twenty-five thousand, seven hundred forty-seven".