21760665 has 8 divisors (see below), whose sum is σ = 34817088. Its totient is φ = 11605680.

The previous prime is 21760639. The next prime is 21760679. The reversal of 21760665 is 56606712.

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

It is not a de Polignac number, because 21760665 - 2⁵ = 21760633 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 725341 + ... + 725370.

It is an arithmetic number, because the mean of its divisors is an integer number (4352136).

Almost surely, 2^21760665 is an apocalyptic number.

It is an amenable number.

21760665 is a deficient number, since it is larger than the sum of its proper divisors (13056423).

21760665 is a wasteful number, since it uses less digits than its factorization.

21760665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1450719.

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 21760665 is about 4664.8327944311. The cubic root of 21760665 is about 279.1841258356.

The spelling of 21760665 in words is "twenty-one million, seven hundred sixty thousand, six hundred sixty-five".