21415463 has 4 divisors (see below), whose sum is σ = 21440760. Its totient is φ = 21390168.

The previous prime is 21415441. The next prime is 21415469. The reversal of 21415463 is 36451412.

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 21415463 - 2²⁴ = 4638247 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 (21415469) 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, 11333 + ... + 13086.

It is an arithmetic number, because the mean of its divisors is an integer number (5360190).

Almost surely, 2^21415463 is an apocalyptic number.

21415463 is a deficient number, since it is larger than the sum of its proper divisors (25297).

21415463 is an equidigital number, since it uses as much as digits as its factorization.

21415463 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25296.

The product of its digits is 2880, while the sum is 26.

The square root of 21415463 is about 4627.6844101559. The cubic root of 21415463 is about 277.6999635490.

Adding to 21415463 its reverse (36451412), we get a palindrome (57866875).

The spelling of 21415463 in words is "twenty-one million, four hundred fifteen thousand, four hundred sixty-three".