21731269 has 8 divisors (see below), whose sum is σ = 26143040. Its totient is φ = 17646336.

The previous prime is 21731263. The next prime is 21731273. The reversal of 21731269 is 96213712.

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 21731269 - 2⁷ = 21731141 is a prime.

It is a super-2 number, since 2×21731269² = 944496104700722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21731269.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21731263) 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, 81564 + ... + 81829.

It is an arithmetic number, because the mean of its divisors is an integer number (3267880).

Almost surely, 2^21731269 is an apocalyptic number.

It is an amenable number.

21731269 is a deficient number, since it is larger than the sum of its proper divisors (4411771).

21731269 is a wasteful number, since it uses less digits than its factorization.

21731269 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163419.

The product of its digits is 4536, while the sum is 31.

The square root of 21731269 is about 4661.6809200116. The cubic root of 21731269 is about 279.0583546357.

The spelling of 21731269 in words is "twenty-one million, seven hundred thirty-one thousand, two hundred sixty-nine".