21653264 has 10 divisors (see below), whose sum is σ = 41953230. Its totient is φ = 10826624.

The previous prime is 21653243. The next prime is 21653267. The reversal of 21653264 is 46235612.

It can be written as a sum of positive squares in only one way, i.e., 17572864 + 4080400 = 4192^2 + 2020^2 .

It is not an unprimeable number, because it can be changed into a prime (21653267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 676649 + ... + 676680.

It is an arithmetic number, because the mean of its divisors is an integer number (4195323).

Almost surely, 2^21653264 is an apocalyptic number.

It is an amenable number.

21653264 is a deficient number, since it is larger than the sum of its proper divisors (20299966).

21653264 is a wasteful number, since it uses less digits than its factorization.

21653264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1353337 (or 1353331 counting only the distinct ones).

The product of its digits is 8640, while the sum is 29.

The square root of 21653264 is about 4653.3067812041. The cubic root of 21653264 is about 278.7240583954.

Adding to 21653264 its reverse (46235612), we get a palindrome (67888876).

The spelling of 21653264 in words is "twenty-one million, six hundred fifty-three thousand, two hundred sixty-four".