21254431 has 8 divisors (see below), whose sum is σ = 23624784. Its totient is φ = 18957120.

The previous prime is 21254417. The next prime is 21254447. The reversal of 21254431 is 13445212.

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 21254431 - 2⁵ = 21254399 is a prime.

It is a super-2 number, since 2×21254431² = 903501674267522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21254411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17646 + ... + 18811.

It is an arithmetic number, because the mean of its divisors is an integer number (2953098).

Almost surely, 2^21254431 is an apocalyptic number.

21254431 is a deficient number, since it is larger than the sum of its proper divisors (2370353).

21254431 is a wasteful number, since it uses less digits than its factorization.

21254431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36521.

The product of its digits is 960, while the sum is 22.

The square root of 21254431 is about 4610.2528130245. The cubic root of 21254431 is about 277.0021634415.

Adding to 21254431 its reverse (13445212), we get a palindrome (34699643).

It can be divided in two parts, 2125 and 4431, that added together give a palindrome (6556).

The spelling of 21254431 in words is "twenty-one million, two hundred fifty-four thousand, four hundred thirty-one".