21948290 has 64 divisors (see below), whose sum is σ = 49351680. Its totient is φ = 6842880.

The previous prime is 21948263. The next prime is 21948293. The reversal of 21948290 is 9284912.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 21948290.

It is not an unprimeable number, because it can be changed into a prime (21948293) by changing a digit.

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, 80855 + ... + 81125.

It is an arithmetic number, because the mean of its divisors is an integer number (771120).

Almost surely, 2^21948290 is an apocalyptic number.

21948290 is an abundant number, since it is smaller than the sum of its proper divisors (27403390).

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

21948290 is a wasteful number, since it uses less digits than its factorization.

21948290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 21948290 is about 4684.9002123845. The cubic root of 21948290 is about 279.9842253018.

The spelling of 21948290 in words is "twenty-one million, nine hundred forty-eight thousand, two hundred ninety".