21919490 has 8 divisors (see below), whose sum is σ = 39455100. Its totient is φ = 8767792.

The previous prime is 21919487. The next prime is 21919501. The reversal of 21919490 is 9491912.

It can be written as a sum of positive squares in 2 ways, for example, as 18003049 + 3916441 = 4243^2 + 1979^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21919490.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1095965 + ... + 1095984.

Almost surely, 2^21919490 is an apocalyptic number.

21919490 is a deficient number, since it is larger than the sum of its proper divisors (17535610).

21919490 is a wasteful number, since it uses less digits than its factorization.

21919490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2191956.

The product of its (nonzero) digits is 5832, while the sum is 35.

The square root of 21919490 is about 4681.8254986704. The cubic root of 21919490 is about 279.8617089206.

The spelling of 21919490 in words is "twenty-one million, nine hundred nineteen thousand, four hundred ninety".