21377717 has 4 divisors (see below), whose sum is σ = 22502880. Its totient is φ = 20252556.

The previous prime is 21377701. The next prime is 21377723. The reversal of 21377717 is 71777312.

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 not a de Polignac number, because 21377717 - 2⁴ = 21377701 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 (21377767) 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, 562553 + ... + 562590.

It is an arithmetic number, because the mean of its divisors is an integer number (5625720).

Almost surely, 2^21377717 is an apocalyptic number.

It is an amenable number.

21377717 is a deficient number, since it is larger than the sum of its proper divisors (1125163).

21377717 is a wasteful number, since it uses less digits than its factorization.

21377717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1125162.

The product of its digits is 14406, while the sum is 35.

The square root of 21377717 is about 4623.6043299573. The cubic root of 21377717 is about 277.5367134825.

The spelling of 21377717 in words is "twenty-one million, three hundred seventy-seven thousand, seven hundred seventeen".