21673760 has 24 divisors (see below), whose sum is σ = 51204636. Its totient is φ = 8669440.

The previous prime is 21673753. The next prime is 21673787. The reversal of 21673760 is 6737612.

It can be written as a sum of positive squares in 2 ways, for example, as 20106256 + 1567504 = 4484^2 + 1252^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67571 + ... + 67890.

Almost surely, 2^21673760 is an apocalyptic number.

21673760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21673760 is an abundant number, since it is smaller than the sum of its proper divisors (29530876).

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

21673760 is a wasteful number, since it uses less digits than its factorization.

21673760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135476 (or 135468 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 32.

The square root of 21673760 is about 4655.5085651301. The cubic root of 21673760 is about 278.8119731901.

The spelling of 21673760 in words is "twenty-one million, six hundred seventy-three thousand, seven hundred sixty".