20977791 has 8 divisors (see below), whose sum is σ = 28353840. Its totient is φ = 13793472.

The previous prime is 20977783. The next prime is 20977799. The reversal of 20977791 is 19777902.

It is an interprime number because it is at equal distance from previous prime (20977783) and next prime (20977799).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20977791 - 2³ = 20977783 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20977799) 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 7 ways as a sum of consecutive naturals, for example, 47676 + ... + 48113.

It is an arithmetic number, because the mean of its divisors is an integer number (3544230).

Almost surely, 2^20977791 is an apocalyptic number.

20977791 is a deficient number, since it is larger than the sum of its proper divisors (7376049).

20977791 is an equidigital number, since it uses as much as digits as its factorization.

20977791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95865.

The product of its (nonzero) digits is 55566, while the sum is 42.

The square root of 20977791 is about 4580.1518533778. The cubic root of 20977791 is about 275.7951246859.

The spelling of 20977791 in words is "twenty million, nine hundred seventy-seven thousand, seven hundred ninety-one".