21930270 has 64 divisors (see below), whose sum is σ = 56471040. Its totient is φ = 5436288.

The previous prime is 21930269. The next prime is 21930281. The reversal of 21930270 is 7203912.

It is a self number, because there is not a number n which added to its sum of digits gives 21930270.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 25101 + ... + 25959.

It is an arithmetic number, because the mean of its divisors is an integer number (882360).

Almost surely, 2^21930270 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21930270, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28235520).

21930270 is an abundant number, since it is smaller than the sum of its proper divisors (34540770).

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

21930270 is a wasteful number, since it uses less digits than its factorization.

21930270 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 929.

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

The square root of 21930270 is about 4682.9766174945. The cubic root of 21930270 is about 279.9075800424.

The spelling of 21930270 in words is "twenty-one million, nine hundred thirty thousand, two hundred seventy".