21798380 has 12 divisors (see below), whose sum is σ = 45776640. Its totient is φ = 8719344.

The previous prime is 21798379. The next prime is 21798389. The reversal of 21798380 is 8389712.

It is not an unprimeable number, because it can be changed into a prime (21798389) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 544940 + ... + 544979.

It is an arithmetic number, because the mean of its divisors is an integer number (3814720).

Almost surely, 2^21798380 is an apocalyptic number.

21798380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21798380 is an abundant number, since it is smaller than the sum of its proper divisors (23978260).

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

21798380 is a wasteful number, since it uses less digits than its factorization.

21798380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1089928 (or 1089926 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 21798380 is about 4668.8735258090. The cubic root of 21798380 is about 279.3453242189.

The spelling of 21798380 in words is "twenty-one million, seven hundred ninety-eight thousand, three hundred eighty".