21621275120623 has 2 divisors, whose sum is σ = 21621275120624. Its totient is φ = 21621275120622.

The previous prime is 21621275120617. The next prime is 21621275120647. The reversal of 21621275120623 is 32602157212612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21621275120623 - 2¹⁷ = 21621274989551 is a prime.

It is a super-2 number, since 2×21621275120623² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21621275120663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810637560311 + 10810637560312.

It is an arithmetic number, because the mean of its divisors is an integer number (10810637560312).

Almost surely, 2^{21621275120623} is an apocalyptic number.

21621275120623 is a deficient number, since it is larger than the sum of its proper divisors (1).

21621275120623 is an equidigital number, since it uses as much as digits as its factorization.

21621275120623 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 21621275120623 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred seventy-five million, one hundred twenty thousand, six hundred twenty-three".