21732665 has 8 divisors (see below), whose sum is σ = 26715528. Its totient is φ = 16961920.

The previous prime is 21732661. The next prime is 21732671. The reversal of 21732665 is 56623712.

It can be written as a sum of positive squares in 4 ways, for example, as 7744 + 21724921 = 88^2 + 4661^2 .

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

It is not a de Polignac number, because 21732665 - 2² = 21732661 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21732661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52802 + ... + 53211.

It is an arithmetic number, because the mean of its divisors is an integer number (3339441).

Almost surely, 2^21732665 is an apocalyptic number.

It is an amenable number.

21732665 is a deficient number, since it is larger than the sum of its proper divisors (4982863).

21732665 is a wasteful number, since it uses less digits than its factorization.

21732665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106059.

The product of its digits is 15120, while the sum is 32.

The square root of 21732665 is about 4661.8306490047. The cubic root of 21732665 is about 279.0643300058.

The spelling of 21732665 in words is "twenty-one million, seven hundred thirty-two thousand, six hundred sixty-five".