21533540533431 has 4 divisors (see below), whose sum is σ = 28711387377912. Its totient is φ = 14355693688952.

The previous prime is 21533540533409. The next prime is 21533540533433. The reversal of 21533540533431 is 13433504533512.

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 21533540533431 - 2¹³ = 21533540525239 is a prime.

It is a super-2 number, since 2×21533540533431² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21533540533433) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3588923422236 + ... + 3588923422241.

It is an arithmetic number, because the mean of its divisors is an integer number (7177846844478).

Almost surely, 2^{21533540533431} is an apocalyptic number.

21533540533431 is a deficient number, since it is larger than the sum of its proper divisors (7177846844481).

21533540533431 is an equidigital number, since it uses as much as digits as its factorization.

21533540533431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7177846844480.

The product of its (nonzero) digits is 972000, while the sum is 42.

The spelling of 21533540533431 in words is "twenty-one trillion, five hundred thirty-three billion, five hundred forty million, five hundred thirty-three thousand, four hundred thirty-one".