21421380971 has 2 divisors, whose sum is σ = 21421380972. Its totient is φ = 21421380970.

The previous prime is 21421380949. The next prime is 21421380997. The reversal of 21421380971 is 17908312412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21421380971 is a prime.

It is not a weakly prime, because it can be changed into another prime (21421380271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710690485 + 10710690486.

It is an arithmetic number, because the mean of its divisors is an integer number (10710690486).

Almost surely, 2^21421380971 is an apocalyptic number.

21421380971 is a deficient number, since it is larger than the sum of its proper divisors (1).

21421380971 is an equidigital number, since it uses as much as digits as its factorization.

21421380971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 38.

The spelling of 21421380971 in words is "twenty-one billion, four hundred twenty-one million, three hundred eighty thousand, nine hundred seventy-one".