21779042 has 4 divisors (see below), whose sum is σ = 32668566. Its totient is φ = 10889520.

The previous prime is 21779033. The next prime is 21779063. The reversal of 21779042 is 24097712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20967241 + 811801 = 4579^2 + 901^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5444759 + ... + 5444762.

Almost surely, 2^21779042 is an apocalyptic number.

21779042 is a deficient number, since it is larger than the sum of its proper divisors (10889524).

21779042 is a wasteful number, since it uses less digits than its factorization.

21779042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10889523.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 21779042 is about 4666.8021170819. The cubic root of 21779042 is about 279.2626945603.

The spelling of 21779042 in words is "twenty-one million, seven hundred seventy-nine thousand, forty-two".