21749960 has 32 divisors (see below), whose sum is σ = 49109760. Its totient is φ = 8669376.

The previous prime is 21749951. The next prime is 21749989. The reversal of 21749960 is 6994712.

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 7 ways as a sum of consecutive naturals, for example, 13097 + ... + 14663.

It is an arithmetic number, because the mean of its divisors is an integer number (1534680).

Almost surely, 2^21749960 is an apocalyptic number.

21749960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21749960 is an abundant number, since it is smaller than the sum of its proper divisors (27359800).

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

21749960 is a wasteful number, since it uses less digits than its factorization.

21749960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1925 (or 1921 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 21749960 is about 4663.6852380923. The cubic root of 21749960 is about 279.1383374634.

The spelling of 21749960 in words is "twenty-one million, seven hundred forty-nine thousand, nine hundred sixty".