21620474535281 has 2 divisors, whose sum is σ = 21620474535282. Its totient is φ = 21620474535280.

The previous prime is 21620474535271. The next prime is 21620474535329. The reversal of 21620474535281 is 18253547402612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15603756125281 + 6016718410000 = 3950159^2 + 2452900^2 .

It is a cyclic number.

It is not a de Polignac number, because 21620474535281 - 2¹⁸ = 21620474273137 is a prime.

It is a super-2 number, since 2×21620474535281² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21620474535271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810237267640 + 10810237267641.

It is an arithmetic number, because the mean of its divisors is an integer number (10810237267641).

Almost surely, 2^{21620474535281} is an apocalyptic number.

It is an amenable number.

21620474535281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21620474535281 is an equidigital number, since it uses as much as digits as its factorization.

21620474535281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3225600, while the sum is 50.

The spelling of 21620474535281 in words is "twenty-one trillion, six hundred twenty billion, four hundred seventy-four million, five hundred thirty-five thousand, two hundred eighty-one".