21453431 has 8 divisors (see below), whose sum is σ = 22264704. Its totient is φ = 20656440.

The previous prime is 21453427. The next prime is 21453433. The reversal of 21453431 is 13435412.

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

It is a cyclic number.

It is not a de Polignac number, because 21453431 - 2² = 21453427 is a prime.

It is a super-2 number, since 2×21453431² = 920499403343522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21453397 and 21453406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21453433) 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, 461 + ... + 6566.

It is an arithmetic number, because the mean of its divisors is an integer number (2783088).

Almost surely, 2^21453431 is an apocalyptic number.

21453431 is a deficient number, since it is larger than the sum of its proper divisors (811273).

21453431 is an equidigital number, since it uses as much as digits as its factorization.

21453431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7141.

The product of its digits is 1440, while the sum is 23.

The square root of 21453431 is about 4631.7848611523. The cubic root of 21453431 is about 277.8639803512.

Adding to 21453431 its reverse (13435412), we get a palindrome (34888843).

The spelling of 21453431 in words is "twenty-one million, four hundred fifty-three thousand, four hundred thirty-one".