21691453 has 8 divisors (see below), whose sum is σ = 24822720. Its totient is φ = 18568320.

The previous prime is 21691447. The next prime is 21691457. The reversal of 21691453 is 35419612.

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 21691453 - 2⁵ = 21691421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21691457) 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, 5613 + ... + 8653.

It is an arithmetic number, because the mean of its divisors is an integer number (3102840).

Almost surely, 2^21691453 is an apocalyptic number.

It is an amenable number.

21691453 is a deficient number, since it is larger than the sum of its proper divisors (3131267).

21691453 is a wasteful number, since it uses less digits than its factorization.

21691453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4067.

The product of its digits is 6480, while the sum is 31.

The square root of 21691453 is about 4657.4083995286. The cubic root of 21691453 is about 278.8878203362.

The spelling of 21691453 in words is "twenty-one million, six hundred ninety-one thousand, four hundred fifty-three".