21948380 has 12 divisors (see below), whose sum is σ = 46091640. Its totient is φ = 8779344.

The previous prime is 21948323. The next prime is 21948391. The reversal of 21948380 is 8384912.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21948380.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 548690 + ... + 548729.

It is an arithmetic number, because the mean of its divisors is an integer number (3840970).

Almost surely, 2^21948380 is an apocalyptic number.

21948380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21948380 is an abundant number, since it is smaller than the sum of its proper divisors (24143260).

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

21948380 is a wasteful number, since it uses less digits than its factorization.

21948380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1097428 (or 1097426 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 21948380 is about 4684.9098177019. The cubic root of 21948380 is about 279.9846079974.

The spelling of 21948380 in words is "twenty-one million, nine hundred forty-eight thousand, three hundred eighty".