21097230 has 64 divisors (see below), whose sum is σ = 63134208. Its totient is φ = 4383360.

The previous prime is 21097229. The next prime is 21097231. The reversal of 21097230 is 3279012.

It is an interprime number because it is at equal distance from previous prime (21097229) and next prime (21097231).

It is a super-2 number, since 2×21097230² = 890186227345800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21097230.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21097231) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2257 + ... + 6876.

It is an arithmetic number, because the mean of its divisors is an integer number (986472).

Almost surely, 2^21097230 is an apocalyptic number.

21097230 is an abundant number, since it is smaller than the sum of its proper divisors (42036978).

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

21097230 is a wasteful number, since it uses less digits than its factorization.

21097230 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9161.

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 21097230 is about 4593.1721065077. The cubic root of 21097230 is about 276.3175561458.

It can be divided in two parts, 2109 and 7230, that added together give a palindrome (9339).

The spelling of 21097230 in words is "twenty-one million, ninety-seven thousand, two hundred thirty".