21928490 has 8 divisors (see below), whose sum is σ = 39471300. Its totient is φ = 8771392.

The previous prime is 21928469. The next prime is 21928493. The reversal of 21928490 is 9482912.

It can be written as a sum of positive squares in 2 ways, for example, as 20313049 + 1615441 = 4507^2 + 1271^2 .

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 21928490.

It is not an unprimeable number, because it can be changed into a prime (21928493) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1096415 + ... + 1096434.

Almost surely, 2^21928490 is an apocalyptic number.

21928490 is a deficient number, since it is larger than the sum of its proper divisors (17542810).

21928490 is a wasteful number, since it uses less digits than its factorization.

21928490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2192856.

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

The square root of 21928490 is about 4682.7865635752. The cubic root of 21928490 is about 279.9000068118.

The spelling of 21928490 in words is "twenty-one million, nine hundred twenty-eight thousand, four hundred ninety".