21772790 has 16 divisors (see below), whose sum is σ = 42205968. Its totient is φ = 8039136.

The previous prime is 21772787. The next prime is 21772811. The reversal of 21772790 is 9727712.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21772790.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 83612 + ... + 83871.

It is an arithmetic number, because the mean of its divisors is an integer number (2637873).

Almost surely, 2^21772790 is an apocalyptic number.

21772790 is a deficient number, since it is larger than the sum of its proper divisors (20433178).

21772790 is a wasteful number, since it uses less digits than its factorization.

21772790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167503.

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

The square root of 21772790 is about 4666.1322313025. The cubic root of 21772790 is about 279.2359698241.

The spelling of 21772790 in words is "twenty-one million, seven hundred seventy-two thousand, seven hundred ninety".