21772079 has 12 divisors (see below), whose sum is σ = 25278672. Its totient is φ = 18369120.

The previous prime is 21772067. The next prime is 21772097. The reversal of 21772079 is 97027712.

It is not a de Polignac number, because 21772079 - 2⁴ = 21772063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21772379) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34979 + ... + 35595.

It is an arithmetic number, because the mean of its divisors is an integer number (2106556).

Almost surely, 2^21772079 is an apocalyptic number.

21772079 is a deficient number, since it is larger than the sum of its proper divisors (3506593).

21772079 is an frugal number, since it uses more digits than its factorization.

21772079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 766 (or 695 counting only the distinct ones).

The product of its (nonzero) digits is 12348, while the sum is 35.

The square root of 21772079 is about 4666.0560433840. The cubic root of 21772079 is about 279.2329302667.

The spelling of 21772079 in words is "twenty-one million, seven hundred seventy-two thousand, seventy-nine".