21481490 has 8 divisors (see below), whose sum is σ = 38666700. Its totient is φ = 8592592.

The previous prime is 21481469. The next prime is 21481501. The reversal of 21481490 is 9418412.

It can be written as a sum of positive squares in 2 ways, for example, as 21409129 + 72361 = 4627^2 + 269^2 .

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

It is a super-2 number, since 2×21481490² = 922908825240200, which contains 22 as substring.

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, 1074065 + ... + 1074084.

Almost surely, 2^21481490 is an apocalyptic number.

21481490 is a deficient number, since it is larger than the sum of its proper divisors (17185210).

21481490 is a wasteful number, since it uses less digits than its factorization.

21481490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2148156.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 21481490 is about 4634.8128333300. The cubic root of 21481490 is about 277.9850672586.

The spelling of 21481490 in words is "twenty-one million, four hundred eighty-one thousand, four hundred ninety".