21407995309 has 2 divisors, whose sum is σ = 21407995310. Its totient is φ = 21407995308.

The previous prime is 21407995303. The next prime is 21407995339. The reversal of 21407995309 is 90359970412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18102895209 + 3305100100 = 134547^2 + 57490^2 .

It is a cyclic number.

It is not a de Polignac number, because 21407995309 - 2⁷ = 21407995181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21407995303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10703997654 + 10703997655.

It is an arithmetic number, because the mean of its divisors is an integer number (10703997655).

Almost surely, 2^21407995309 is an apocalyptic number.

It is an amenable number.

21407995309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21407995309 is an equidigital number, since it uses as much as digits as its factorization.

21407995309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 612360, while the sum is 49.

The spelling of 21407995309 in words is "twenty-one billion, four hundred seven million, nine hundred ninety-five thousand, three hundred nine".