21315454 has 16 divisors (see below), whose sum is σ = 33811200. Its totient is φ = 10050264.

The previous prime is 21315451. The next prime is 21315491. The reversal of 21315454 is 45451312.

It is a happy number.

It is a super-2 number, since 2×21315454² = 908697158452232, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315451) 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, 7909 + ... + 10255.

It is an arithmetic number, because the mean of its divisors is an integer number (2113200).

Almost surely, 2^21315454 is an apocalyptic number.

21315454 is a deficient number, since it is larger than the sum of its proper divisors (12495746).

21315454 is a wasteful number, since it uses less digits than its factorization.

21315454 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2607.

The product of its digits is 2400, while the sum is 25.

The square root of 21315454 is about 4616.8662532068. The cubic root of 21315454 is about 277.2670078515.

Adding to 21315454 its reverse (45451312), we get a palindrome (66766766).

The spelling of 21315454 in words is "twenty-one million, three hundred fifteen thousand, four hundred fifty-four".