21413661 has 8 divisors (see below), whose sum is σ = 28913280. Its totient is φ = 14094912.

The previous prime is 21413647. The next prime is 21413677. The reversal of 21413661 is 16631412.

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

It is not a de Polignac number, because 21413661 - 2⁷ = 21413533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21413611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44940 + ... + 45413.

It is an arithmetic number, because the mean of its divisors is an integer number (3614160).

Almost surely, 2^21413661 is an apocalyptic number.

It is an amenable number.

21413661 is a deficient number, since it is larger than the sum of its proper divisors (7499619).

21413661 is an equidigital number, since it uses as much as digits as its factorization.

21413661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90435.

The product of its digits is 864, while the sum is 24.

The square root of 21413661 is about 4627.4897082544. The cubic root of 21413661 is about 277.6921743273.

The spelling of 21413661 in words is "twenty-one million, four hundred thirteen thousand, six hundred sixty-one".