21311411971 has 2 divisors, whose sum is σ = 21311411972. Its totient is φ = 21311411970.

The previous prime is 21311411941. The next prime is 21311411977. The reversal of 21311411971 is 17911411312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21311411971 - 2⁷ = 21311411843 is a prime.

It is not a weakly prime, because it can be changed into another prime (21311411977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655705985 + 10655705986.

It is an arithmetic number, because the mean of its divisors is an integer number (10655705986).

Almost surely, 2^21311411971 is an apocalyptic number.

21311411971 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311411971 is an equidigital number, since it uses as much as digits as its factorization.

21311411971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1512, while the sum is 31.

The spelling of 21311411971 in words is "twenty-one billion, three hundred eleven million, four hundred eleven thousand, nine hundred seventy-one".