21660076 has 24 divisors (see below), whose sum is σ = 40302080. Its totient is φ = 10156752.

The previous prime is 21660053. The next prime is 21660077. The reversal of 21660076 is 67006612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21660077) 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, 6445 + ... + 9211.

Almost surely, 2^21660076 is an apocalyptic number.

It is an amenable number.

21660076 is a deficient number, since it is larger than the sum of its proper divisors (18642004).

21660076 is a wasteful number, since it uses less digits than its factorization.

21660076 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2893 (or 2891 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21660076 is about 4654.0386762467. The cubic root of 21660076 is about 278.7532836925.

Adding to 21660076 its reverse (67006612), we get a palindrome (88666688).

The spelling of 21660076 in words is "twenty-one million, six hundred sixty thousand, seventy-six".