21258463 has 4 divisors (see below), whose sum is σ = 22182768. Its totient is φ = 20334160.

The previous prime is 21258443. The next prime is 21258481. The reversal of 21258463 is 36485212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21258463 - 2⁵ = 21258431 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21258443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 462118 + ... + 462163.

It is an arithmetic number, because the mean of its divisors is an integer number (5545692).

Almost surely, 2^21258463 is an apocalyptic number.

21258463 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21258463 is a deficient number, since it is larger than the sum of its proper divisors (924305).

21258463 is an equidigital number, since it uses as much as digits as its factorization.

21258463 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 924304.

The product of its digits is 11520, while the sum is 31.

The square root of 21258463 is about 4610.6900785023. The cubic root of 21258463 is about 277.0196782538.

The spelling of 21258463 in words is "twenty-one million, two hundred fifty-eight thousand, four hundred sixty-three".