21292530 has 64 divisors (see below), whose sum is σ = 59851008. Its totient is φ = 4746240.

The previous prime is 21292519. The next prime is 21292541. The reversal of 21292530 is 3529212.

It is an interprime number because it is at equal distance from previous prime (21292519) and next prime (21292541).

It is a self number, because there is not a number n which added to its sum of digits gives 21292530.

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, 7374 + ... + 9846.

It is an arithmetic number, because the mean of its divisors is an integer number (935172).

Almost surely, 2^21292530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21292530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29925504).

21292530 is an abundant number, since it is smaller than the sum of its proper divisors (38558478).

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

21292530 is a wasteful number, since it uses less digits than its factorization.

21292530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2531.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 21292530 is about 4614.3829489976. The cubic root of 21292530 is about 277.1675753174.

The spelling of 21292530 in words is "twenty-one million, two hundred ninety-two thousand, five hundred thirty".