21097400 has 48 divisors (see below), whose sum is σ = 50394840. Its totient is φ = 8208000.

The previous prime is 21097393. The next prime is 21097421. The reversal of 21097400 is 479012.

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 11 ways as a sum of consecutive naturals, for example, 5975 + ... + 8825.

Almost surely, 2^21097400 is an apocalyptic number.

21097400 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 21097400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25197420).

21097400 is an abundant number, since it is smaller than the sum of its proper divisors (29297440).

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

21097400 is a wasteful number, since it uses less digits than its factorization.

21097400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2904 (or 2895 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 21097400 is about 4593.1906121998. The cubic root of 21097400 is about 276.3182983263.

The spelling of 21097400 in words is "twenty-one million, ninety-seven thousand, four hundred".