21463831 has 2 divisors, whose sum is σ = 21463832. Its totient is φ = 21463830.

The previous prime is 21463801. The next prime is 21463847. The reversal of 21463831 is 13836412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21463831 - 2¹³ = 21455639 is a prime.

It is a super-2 number, since 2×21463831² = 921392082393122, 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 21463831.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21463801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10731915 + 10731916.

It is an arithmetic number, because the mean of its divisors is an integer number (10731916).

Almost surely, 2^21463831 is an apocalyptic number.

21463831 is a deficient number, since it is larger than the sum of its proper divisors (1).

21463831 is an equidigital number, since it uses as much as digits as its factorization.

21463831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 28.

The square root of 21463831 is about 4632.9074024850. The cubic root of 21463831 is about 277.9088732258.

The spelling of 21463831 in words is "twenty-one million, four hundred sixty-three thousand, eight hundred thirty-one".