21098340 has 96 divisors (see below), whose sum is σ = 66528000. Its totient is φ = 5550336.

The previous prime is 21098339. The next prime is 21098353. The reversal of 21098340 is 4389012.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 47841 + ... + 48279.

It is an arithmetic number, because the mean of its divisors is an integer number (693000).

Almost surely, 2^21098340 is an apocalyptic number.

21098340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21098340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33264000).

21098340 is an abundant number, since it is smaller than the sum of its proper divisors (45429660).

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

21098340 is a wasteful number, since it uses less digits than its factorization.

21098340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 546 (or 538 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21098340 is about 4593.2929364455. The cubic root of 21098340 is about 276.3224020759.

The spelling of 21098340 in words is "twenty-one million, ninety-eight thousand, three hundred forty".