21772742791 has 2 divisors, whose sum is σ = 21772742792. Its totient is φ = 21772742790.

The previous prime is 21772742777. The next prime is 21772742861. The reversal of 21772742791 is 19724727712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21772742791 - 2¹⁵ = 21772710023 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21772742711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10886371395 + 10886371396.

It is an arithmetic number, because the mean of its divisors is an integer number (10886371396).

Almost surely, 2^21772742791 is an apocalyptic number.

21772742791 is a deficient number, since it is larger than the sum of its proper divisors (1).

21772742791 is an equidigital number, since it uses as much as digits as its factorization.

21772742791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 691488, while the sum is 49.

The spelling of 21772742791 in words is "twenty-one billion, seven hundred seventy-two million, seven hundred forty-two thousand, seven hundred ninety-one".