20999377 has 4 divisors (see below), whose sum is σ = 23999296. Its totient is φ = 17999460.

The previous prime is 20999359. The next prime is 20999383. The reversal of 20999377 is 77399902.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20999377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20999317) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1499949 + ... + 1499962.

It is an arithmetic number, because the mean of its divisors is an integer number (5999824).

Almost surely, 2^20999377 is an apocalyptic number.

It is an amenable number.

20999377 is a deficient number, since it is larger than the sum of its proper divisors (2999919).

20999377 is an equidigital number, since it uses as much as digits as its factorization.

20999377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2999918.

The product of its (nonzero) digits is 214326, while the sum is 46.

The square root of 20999377 is about 4582.5077195789. The cubic root of 20999377 is about 275.8896893417.

It can be divided in two parts, 2099 and 9377, that added together give a triangular number (11476 = T₁₅₁).

The spelling of 20999377 in words is "twenty million, nine hundred ninety-nine thousand, three hundred seventy-seven".