20722778 has 4 divisors (see below), whose sum is σ = 31084170. Its totient is φ = 10361388.

The previous prime is 20722769. The next prime is 20722781. The reversal of 20722778 is 87722702.

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., 16507969 + 4214809 = 4063^2 + 2053^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5180693 + ... + 5180696.

Almost surely, 2^20722778 is an apocalyptic number.

20722778 is a deficient number, since it is larger than the sum of its proper divisors (10361392).

20722778 is a wasteful number, since it uses less digits than its factorization.

20722778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10361391.

The product of its (nonzero) digits is 21952, while the sum is 35.

The square root of 20722778 is about 4552.2278062505. The cubic root of 20722778 is about 274.6730130052.

The spelling of 20722778 in words is "twenty million, seven hundred twenty-two thousand, seven hundred seventy-eight".