21790477 has 4 divisors (see below), whose sum is σ = 22115776. Its totient is φ = 21465180.

The previous prime is 21790471. The next prime is 21790487. The reversal of 21790477 is 77409712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21790477 - 2¹⁵ = 21757709 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 (21790471) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 162549 + ... + 162682.

It is an arithmetic number, because the mean of its divisors is an integer number (5528944).

Almost surely, 2^21790477 is an apocalyptic number.

It is an amenable number.

21790477 is a deficient number, since it is larger than the sum of its proper divisors (325299).

21790477 is an equidigital number, since it uses as much as digits as its factorization.

21790477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325298.

The product of its (nonzero) digits is 24696, while the sum is 37.

The square root of 21790477 is about 4668.0270993215. The cubic root of 21790477 is about 279.3115612673.

The spelling of 21790477 in words is "twenty-one million, seven hundred ninety thousand, four hundred seventy-seven".