20291977 has 4 divisors (see below), whose sum is σ = 20405520. Its totient is φ = 20178436.

The previous prime is 20291969. The next prime is 20291983. The reversal of 20291977 is 77919202.

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, and also an emirpimes, since its reverse is a distinct semiprime: 77919202 = 2 ⋅38959601.

It is a cyclic number.

It is not a de Polignac number, because 20291977 - 2³ = 20291969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20291987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56503 + ... + 56860.

It is an arithmetic number, because the mean of its divisors is an integer number (5101380).

Almost surely, 2^20291977 is an apocalyptic number.

It is an amenable number.

20291977 is a deficient number, since it is larger than the sum of its proper divisors (113543).

20291977 is a wasteful number, since it uses less digits than its factorization.

20291977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113542.

The product of its (nonzero) digits is 15876, while the sum is 37.

The square root of 20291977 is about 4504.6616965095. The cubic root of 20291977 is about 272.7562978772.

The spelling of 20291977 in words is "twenty million, two hundred ninety-one thousand, nine hundred seventy-seven".