21331309801 has 2 divisors, whose sum is σ = 21331309802. Its totient is φ = 21331309800.

The previous prime is 21331309771. The next prime is 21331309807. The reversal of 21331309801 is 10890313312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11599290000 + 9732019801 = 107700^2 + 98651^2 .

It is a cyclic number.

It is not a de Polignac number, because 21331309801 - 2²¹ = 21329212649 is a prime.

It is not a weakly prime, because it can be changed into another prime (21331309807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665654900 + 10665654901.

It is an arithmetic number, because the mean of its divisors is an integer number (10665654901).

Almost surely, 2^21331309801 is an apocalyptic number.

It is an amenable number.

21331309801 is a deficient number, since it is larger than the sum of its proper divisors (1).

21331309801 is an equidigital number, since it uses as much as digits as its factorization.

21331309801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 31.

The spelling of 21331309801 in words is "twenty-one billion, three hundred thirty-one million, three hundred nine thousand, eight hundred one".