21620713221231 has 4 divisors (see below), whose sum is σ = 28827617628312. Its totient is φ = 14413808814152.

The previous prime is 21620713221221. The next prime is 21620713221269. The reversal of 21620713221231 is 13212231702612.

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 21620713221231 - 2¹⁷ = 21620713090159 is a prime.

It is a super-2 number, since 2×21620713221231² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21620713221192 and 21620713221201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21620713221221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3603452203536 + ... + 3603452203541.

It is an arithmetic number, because the mean of its divisors is an integer number (7206904407078).

Almost surely, 2^{21620713221231} is an apocalyptic number.

21620713221231 is a deficient number, since it is larger than the sum of its proper divisors (7206904407081).

21620713221231 is an equidigital number, since it uses as much as digits as its factorization.

21620713221231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7206904407080.

The product of its (nonzero) digits is 12096, while the sum is 33.

Adding to 21620713221231 its reverse (13212231702612), we get a palindrome (34832944923843).

The spelling of 21620713221231 in words is "twenty-one trillion, six hundred twenty billion, seven hundred thirteen million, two hundred twenty-one thousand, two hundred thirty-one".