21490641 has 24 divisors (see below), whose sum is σ = 31799040. Its totient is φ = 13982976.

The previous prime is 21490627. The next prime is 21490643. The reversal of 21490641 is 14609412.

21490641 is a `hidden beast` number, since 2 + 14 + 9 + 0 + 641 = 666.

It is not a de Polignac number, because 21490641 - 2⁹ = 21490129 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21490643) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 89800 + ... + 90038.

It is an arithmetic number, because the mean of its divisors is an integer number (1324960).

Almost surely, 2^21490641 is an apocalyptic number.

It is an amenable number.

21490641 is a deficient number, since it is larger than the sum of its proper divisors (10308399).

21490641 is a wasteful number, since it uses less digits than its factorization.

21490641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 445 (or 442 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21490641 is about 4635.7999309720. The cubic root of 21490641 is about 278.0245350394.

The spelling of 21490641 in words is "twenty-one million, four hundred ninety thousand, six hundred forty-one".