21739253771 has 2 divisors, whose sum is σ = 21739253772. Its totient is φ = 21739253770.

The previous prime is 21739253707. The next prime is 21739253791. The reversal of 21739253771 is 17735293712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21739253771 - 2⁶ = 21739253707 is a prime.

It is not a weakly prime, because it can be changed into another prime (21739253791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10869626885 + 10869626886.

It is an arithmetic number, because the mean of its divisors is an integer number (10869626886).

Almost surely, 2^21739253771 is an apocalyptic number.

21739253771 is a deficient number, since it is larger than the sum of its proper divisors (1).

21739253771 is an equidigital number, since it uses as much as digits as its factorization.

21739253771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 555660, while the sum is 47.

The spelling of 21739253771 in words is "twenty-one billion, seven hundred thirty-nine million, two hundred fifty-three thousand, seven hundred seventy-one".