21673764 has 48 divisors (see below), whose sum is σ = 64220800. Its totient is φ = 6192288.

The previous prime is 21673753. The next prime is 21673787. The reversal of 21673764 is 46737612.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13579 + ... + 15090.

Almost surely, 2^21673764 is an apocalyptic number.

It is an amenable number.

21673764 is an abundant number, since it is smaller than the sum of its proper divisors (42547036).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21673764 is a wasteful number, since it uses less digits than its factorization.

21673764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28689 (or 28681 counting only the distinct ones).

The product of its digits is 42336, while the sum is 36.

The square root of 21673764 is about 4655.5089947287. The cubic root of 21673764 is about 278.8119903422.

The spelling of 21673764 in words is "twenty-one million, six hundred seventy-three thousand, seven hundred sixty-four".