20779966 has 4 divisors (see below), whose sum is σ = 31169952. Its totient is φ = 10389982.

The previous prime is 20779937. The next prime is 20779973. The reversal of 20779966 is 66997702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66997702 = 2 ⋅33498851.

It is a super-2 number, since 2×20779966² = 863613973922312, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5194990 + ... + 5194993.

It is an arithmetic number, because the mean of its divisors is an integer number (7792488).

Almost surely, 2^20779966 is an apocalyptic number.

20779966 is a deficient number, since it is larger than the sum of its proper divisors (10389986).

20779966 is a wasteful number, since it uses less digits than its factorization.

20779966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10389985.

The product of its (nonzero) digits is 285768, while the sum is 46.

The square root of 20779966 is about 4558.5047987251. The cubic root of 20779966 is about 274.9254497643.

The spelling of 20779966 in words is "twenty million, seven hundred seventy-nine thousand, nine hundred sixty-six".