21748380 has 24 divisors (see below), whose sum is σ = 60895632. Its totient is φ = 5799552.

The previous prime is 21748367. The next prime is 21748399. The reversal of 21748380 is 8384712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 181177 + ... + 181296.

It is an arithmetic number, because the mean of its divisors is an integer number (2537318).

Almost surely, 2^21748380 is an apocalyptic number.

21748380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21748380 is an abundant number, since it is smaller than the sum of its proper divisors (39147252).

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

21748380 is a wasteful number, since it uses less digits than its factorization.

21748380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 362485 (or 362483 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 33.

The square root of 21748380 is about 4663.5158410796. The cubic root of 21748380 is about 279.1315780755.

The spelling of 21748380 in words is "twenty-one million, seven hundred forty-eight thousand, three hundred eighty".