21611493 has 24 divisors (see below), whose sum is σ = 33571200. Its totient is φ = 13353984.

The previous prime is 21611461. The next prime is 21611519. The reversal of 21611493 is 39411612.

21611493 is a `hidden beast` number, since 2 + 1 + 611 + 49 + 3 = 666.

It is not a de Polignac number, because 21611493 - 2⁵ = 21611461 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21611693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6693 + ... + 9381.

It is an arithmetic number, because the mean of its divisors is an integer number (1398800).

Almost surely, 2^21611493 is an apocalyptic number.

It is an amenable number.

21611493 is a deficient number, since it is larger than the sum of its proper divisors (11959707).

21611493 is a wasteful number, since it uses less digits than its factorization.

21611493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2761 (or 2758 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 21611493 is about 4648.8163009523. The cubic root of 21611493 is about 278.5447154999.

The spelling of 21611493 in words is "twenty-one million, six hundred eleven thousand, four hundred ninety-three".