21284690 has 16 divisors (see below), whose sum is σ = 43785792. Its totient is φ = 7297584.

The previous prime is 21284689. The next prime is 21284701. The reversal of 21284690 is 9648212.

It is a super-2 number, since 2×21284690² = 906076056792200, which contains 22 as substring.

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 7 ways as a sum of consecutive naturals, for example, 151964 + ... + 152103.

It is an arithmetic number, because the mean of its divisors is an integer number (2736612).

Almost surely, 2^21284690 is an apocalyptic number.

21284690 is an abundant number, since it is smaller than the sum of its proper divisors (22501102).

21284690 is a wasteful number, since it uses less digits than its factorization.

21284690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304081.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 21284690 is about 4613.5333530820. The cubic root of 21284690 is about 277.1335530484.

The spelling of 21284690 in words is "twenty-one million, two hundred eighty-four thousand, six hundred ninety".