21761490 has 32 divisors (see below), whose sum is σ = 52382016. Its totient is φ = 5785920.

The previous prime is 21761477. The next prime is 21761527. The reversal of 21761490 is 9416712.

It is a happy number.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11769 + ... + 13491.

It is an arithmetic number, because the mean of its divisors is an integer number (1636938).

Almost surely, 2^21761490 is an apocalyptic number.

21761490 is an abundant number, since it is smaller than the sum of its proper divisors (30620526).

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

21761490 is a wasteful number, since it uses less digits than its factorization.

21761490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2154.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 21761490 is about 4664.9212211998. The cubic root of 21761490 is about 279.1876539752.

The spelling of 21761490 in words is "twenty-one million, seven hundred sixty-one thousand, four hundred ninety".