21731453 has 2 divisors, whose sum is σ = 21731454. Its totient is φ = 21731452.

The previous prime is 21731449. The next prime is 21731473. The reversal of 21731453 is 35413712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15038884 + 6692569 = 3878^2 + 2587^2 .

It is a cyclic number.

It is not a de Polignac number, because 21731453 - 2² = 21731449 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21731473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10865726 + 10865727.

It is an arithmetic number, because the mean of its divisors is an integer number (10865727).

Almost surely, 2^21731453 is an apocalyptic number.

It is an amenable number.

21731453 is a deficient number, since it is larger than the sum of its proper divisors (1).

21731453 is an equidigital number, since it uses as much as digits as its factorization.

21731453 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2520, while the sum is 26.

The square root of 21731453 is about 4661.7006553403. The cubic root of 21731453 is about 279.0591422349.

The spelling of 21731453 in words is "twenty-one million, seven hundred thirty-one thousand, four hundred fifty-three".