21533454322537 has 2 divisors, whose sum is σ = 21533454322538. Its totient is φ = 21533454322536.

The previous prime is 21533454322507. The next prime is 21533454322559. The reversal of 21533454322537 is 73522345433512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21449087891856 + 84366430681 = 4631316^2 + 290459^2 .

It is a cyclic number.

It is not a de Polignac number, because 21533454322537 - 2²³ = 21533445933929 is a prime.

It is a super-2 number, since 2×21533454322537² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21533454322507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10766727161268 + 10766727161269.

It is an arithmetic number, because the mean of its divisors is an integer number (10766727161269).

Almost surely, 2^{21533454322537} is an apocalyptic number.

It is an amenable number.

21533454322537 is a deficient number, since it is larger than the sum of its proper divisors (1).

21533454322537 is an equidigital number, since it uses as much as digits as its factorization.

21533454322537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072000, while the sum is 49.

The spelling of 21533454322537 in words is "twenty-one trillion, five hundred thirty-three billion, four hundred fifty-four million, three hundred twenty-two thousand, five hundred thirty-seven".