21377617 has 4 divisors (see below), whose sum is σ = 21533796. Its totient is φ = 21221440.

The previous prime is 21377599. The next prime is 21377627. The reversal of 21377617 is 71677312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18740241 + 2637376 = 4329^2 + 1624^2 .

It is a cyclic number.

It is not a de Polignac number, because 21377617 - 2¹¹ = 21375569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21377627) 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, 77884 + ... + 78157.

It is an arithmetic number, because the mean of its divisors is an integer number (5383449).

Almost surely, 2^21377617 is an apocalyptic number.

It is an amenable number.

21377617 is a deficient number, since it is larger than the sum of its proper divisors (156179).

21377617 is a wasteful number, since it uses less digits than its factorization.

21377617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156178.

The product of its digits is 12348, while the sum is 34.

The square root of 21377617 is about 4623.5935158705. The cubic root of 21377617 is about 277.5362807311.

The spelling of 21377617 in words is "twenty-one million, three hundred seventy-seven thousand, six hundred seventeen".