21939197279 has 2 divisors, whose sum is σ = 21939197280. Its totient is φ = 21939197278.

The previous prime is 21939197239. The next prime is 21939197299. The reversal of 21939197279 is 97279193912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21939197279 - 2¹² = 21939193183 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21939197239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10969598639 + 10969598640.

It is an arithmetic number, because the mean of its divisors is an integer number (10969598640).

Almost surely, 2^21939197279 is an apocalyptic number.

21939197279 is a deficient number, since it is larger than the sum of its proper divisors (1).

21939197279 is an equidigital number, since it uses as much as digits as its factorization.

21939197279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3857868, while the sum is 59.

The spelling of 21939197279 in words is "twenty-one billion, nine hundred thirty-nine million, one hundred ninety-seven thousand, two hundred seventy-nine".