21057677 has 4 divisors (see below), whose sum is σ = 21354336. Its totient is φ = 20761020.

The previous prime is 21057671. The next prime is 21057691. The reversal of 21057677 is 77675012.

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 not a de Polignac number, because 21057677 - 2⁴ = 21057661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21057671) 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, 148223 + ... + 148364.

It is an arithmetic number, because the mean of its divisors is an integer number (5338584).

Almost surely, 2^21057677 is an apocalyptic number.

It is an amenable number.

21057677 is a deficient number, since it is larger than the sum of its proper divisors (296659).

21057677 is an equidigital number, since it uses as much as digits as its factorization.

21057677 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296658.

The product of its (nonzero) digits is 20580, while the sum is 35.

The square root of 21057677 is about 4588.8644564859. The cubic root of 21057677 is about 276.1447684477.

The spelling of 21057677 in words is "twenty-one million, fifty-seven thousand, six hundred seventy-seven".