21487299 has 8 divisors (see below), whose sum is σ = 28775760. Its totient is φ = 14261856.

The previous prime is 21487283. The next prime is 21487307. The reversal of 21487299 is 99278412.

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

It is not a de Polignac number, because 21487299 - 2⁴ = 21487283 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21487299.

It is not an unprimeable number, because it can be changed into a prime (21487699) 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, 14952 + ... + 16325.

It is an arithmetic number, because the mean of its divisors is an integer number (3596970).

Almost surely, 2^21487299 is an apocalyptic number.

21487299 is a deficient number, since it is larger than the sum of its proper divisors (7288461).

21487299 is a wasteful number, since it uses less digits than its factorization.

21487299 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31509.

The product of its digits is 72576, while the sum is 42.

The square root of 21487299 is about 4635.4394613672. The cubic root of 21487299 is about 278.0101224684.

The spelling of 21487299 in words is "twenty-one million, four hundred eighty-seven thousand, two hundred ninety-nine".