20777961 has 16 divisors (see below), whose sum is σ = 29890944. Its totient is φ = 12789504.

The previous prime is 20777957. The next prime is 20777969. The reversal of 20777961 is 16977702.

It is not a de Polignac number, because 20777961 - 2² = 20777957 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20777969) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1141 + ... + 6546.

It is an arithmetic number, because the mean of its divisors is an integer number (1868184).

Almost surely, 2^20777961 is an apocalyptic number.

It is an amenable number.

20777961 is a deficient number, since it is larger than the sum of its proper divisors (9112983).

20777961 is a wasteful number, since it uses less digits than its factorization.

20777961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7760.

The product of its (nonzero) digits is 37044, while the sum is 39.

The square root of 20777961 is about 4558.2848748186. The cubic root of 20777961 is about 274.9166072209.

The spelling of 20777961 in words is "twenty million, seven hundred seventy-seven thousand, nine hundred sixty-one".