21131299 has 6 divisors (see below), whose sum is σ = 24581364. Its totient is φ = 18112500.

The previous prime is 21131293. The next prime is 21131317. The reversal of 21131299 is 99213112.

It is a de Polignac number, because none of the positive numbers 2^k-21131299 is a prime.

It is a super-3 number, since 3×21131299³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21131293) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215577 + ... + 215674.

It is an arithmetic number, because the mean of its divisors is an integer number (4096894).

Almost surely, 2^21131299 is an apocalyptic number.

21131299 is a deficient number, since it is larger than the sum of its proper divisors (3450065).

21131299 is an equidigital number, since it uses as much as digits as its factorization.

21131299 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431265 (or 431258 counting only the distinct ones).

The product of its digits is 972, while the sum is 28.

The square root of 21131299 is about 4596.8792675031. The cubic root of 21131299 is about 276.4662138924.

The spelling of 21131299 in words is "twenty-one million, one hundred thirty-one thousand, two hundred ninety-nine".