21031543571 has 2 divisors, whose sum is σ = 21031543572. Its totient is φ = 21031543570.

The previous prime is 21031543567. The next prime is 21031543573. The reversal of 21031543571 is 17534513012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21031543571 - 2² = 21031543567 is a prime.

Together with 21031543573, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21031543573) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515771785 + 10515771786.

It is an arithmetic number, because the mean of its divisors is an integer number (10515771786).

Almost surely, 2^21031543571 is an apocalyptic number.

21031543571 is a deficient number, since it is larger than the sum of its proper divisors (1).

21031543571 is an equidigital number, since it uses as much as digits as its factorization.

21031543571 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12600, while the sum is 32.

The spelling of 21031543571 in words is "twenty-one billion, thirty-one million, five hundred forty-three thousand, five hundred seventy-one".