21491146 has 8 divisors (see below), whose sum is σ = 33348420. Its totient is φ = 10375008.

The previous prime is 21491101. The next prime is 21491149. The reversal of 21491146 is 64119412.

It can be written as a sum of positive squares in 2 ways, for example, as 21483225 + 7921 = 4635^2 + 89^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21491149) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 185211 + ... + 185326.

Almost surely, 2^21491146 is an apocalyptic number.

21491146 is a deficient number, since it is larger than the sum of its proper divisors (11857274).

21491146 is a wasteful number, since it uses less digits than its factorization.

21491146 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370568.

The product of its digits is 1728, while the sum is 28.

The square root of 21491146 is about 4635.8543980587. The cubic root of 21491146 is about 278.0267127515.

The spelling of 21491146 in words is "twenty-one million, four hundred ninety-one thousand, one hundred forty-six".