21464690 has 32 divisors (see below), whose sum is σ = 41897520. Its totient is φ = 7917312.

The previous prime is 21464687. The next prime is 21464711. The reversal of 21464690 is 9646412.

It is a happy number.

It is a Cunningham number, because it is equal to 4633²+1.

It can be written as a sum of positive squares in 8 ways, for example, as 1 + 21464689 = 1^2 + 4633^2 .

It is a super-2 number, since 2×21464690² = 921465833592200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21482 + ... + 22458.

Almost surely, 2^21464690 is an apocalyptic number.

21464690 is a deficient number, since it is larger than the sum of its proper divisors (20432830).

21464690 is an equidigital number, since it uses as much as digits as its factorization.

21464690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1023 (or 997 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 21464690 is about 4633.0001079214. Note that the first 3 decimals coincide. The cubic root of 21464690 is about 277.9125805562.

The spelling of 21464690 in words is "twenty-one million, four hundred sixty-four thousand, six hundred ninety".