21731469 has 32 divisors (see below), whose sum is σ = 31701120. Its totient is φ = 13208832.

The previous prime is 21731453. The next prime is 21731473. The reversal of 21731469 is 96413712.

It is not a de Polignac number, because 21731469 - 2⁴ = 21731453 is a prime.

It is a super-2 number, since 2×21731469² = 944513489795922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21731419) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 138339 + ... + 138495.

It is an arithmetic number, because the mean of its divisors is an integer number (990660).

Almost surely, 2^21731469 is an apocalyptic number.

21731469 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21731469 is a deficient number, since it is larger than the sum of its proper divisors (9969651).

21731469 is a wasteful number, since it uses less digits than its factorization.

21731469 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269.

The product of its digits is 9072, while the sum is 33.

The square root of 21731469 is about 4661.7023714519. The cubic root of 21731469 is about 279.0592107216.

The spelling of 21731469 in words is "twenty-one million, seven hundred thirty-one thousand, four hundred sixty-nine".