21751530 has 32 divisors (see below), whose sum is σ = 53092800. Its totient is φ = 5701632.

The previous prime is 21751529. The next prime is 21751531. The reversal of 21751530 is 3515712.

It is an interprime number because it is at equal distance from previous prime (21751529) and next prime (21751531).

It is a self number, because there is not a number n which added to its sum of digits gives 21751530.

It is not an unprimeable number, because it can be changed into a prime (21751531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4375 + ... + 7914.

It is an arithmetic number, because the mean of its divisors is an integer number (1659150).

Almost surely, 2^21751530 is an apocalyptic number.

21751530 is an abundant number, since it is smaller than the sum of its proper divisors (31341270).

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

21751530 is a wasteful number, since it uses less digits than its factorization.

21751530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12358.

The product of its (nonzero) digits is 1050, while the sum is 24.

The square root of 21751530 is about 4663.8535568776. The cubic root of 21751530 is about 279.1450537462.

The spelling of 21751530 in words is "twenty-one million, seven hundred fifty-one thousand, five hundred thirty".