21898180 has 24 divisors (see below), whose sum is σ = 47057472. Its totient is φ = 8555232.

The previous prime is 21898153. The next prime is 21898181. The reversal of 21898180 is 8189812.

It is not an unprimeable number, because it can be changed into a prime (21898181) by changing a digit.

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, 11872 + ... + 13591.

It is an arithmetic number, because the mean of its divisors is an integer number (1960728).

Almost surely, 2^21898180 is an apocalyptic number.

21898180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21898180 is an abundant number, since it is smaller than the sum of its proper divisors (25159292).

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

21898180 is a wasteful number, since it uses less digits than its factorization.

21898180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25515 (or 25513 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 37.

The square root of 21898180 is about 4679.5491235802. The cubic root of 21898180 is about 279.7709862086.

The spelling of 21898180 in words is "twenty-one million, eight hundred ninety-eight thousand, one hundred eighty".