21397956304907 has 32 divisors (see below), whose sum is σ = 27288860712960. Its totient is φ = 16321816431360.

The previous prime is 21397956304903. The next prime is 21397956304909. The reversal of 21397956304907 is 70940365979312.

It is a cyclic number.

It is not a de Polignac number, because 21397956304907 - 2² = 21397956304903 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21397956304903) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13678682 + ... + 15162527.

It is an arithmetic number, because the mean of its divisors is an integer number (852776897280).

Almost surely, 2^{21397956304907} is an apocalyptic number.

21397956304907 is a deficient number, since it is larger than the sum of its proper divisors (5890904408053).

21397956304907 is a wasteful number, since it uses less digits than its factorization.

21397956304907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28841523.

The product of its (nonzero) digits is 77157360, while the sum is 65.

The spelling of 21397956304907 in words is "twenty-one trillion, three hundred ninety-seven billion, nine hundred fifty-six million, three hundred four thousand, nine hundred seven".