21977923397 has 2 divisors, whose sum is σ = 21977923398. Its totient is φ = 21977923396.

The previous prime is 21977923367. The next prime is 21977923399. The reversal of 21977923397 is 79332977912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19053385156 + 2924538241 = 138034^2 + 54079^2 .

It is a cyclic number.

It is not a de Polignac number, because 21977923397 - 2¹⁴ = 21977907013 is a prime.

Together with 21977923399, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21977923399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10988961698 + 10988961699.

It is an arithmetic number, because the mean of its divisors is an integer number (10988961699).

Almost surely, 2^21977923397 is an apocalyptic number.

It is an amenable number.

21977923397 is a deficient number, since it is larger than the sum of its proper divisors (1).

21977923397 is an equidigital number, since it uses as much as digits as its factorization.

21977923397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9001692, while the sum is 59.

The spelling of 21977923397 in words is "twenty-one billion, nine hundred seventy-seven million, nine hundred twenty-three thousand, three hundred ninety-seven".