21450513 has 32 divisors (see below), whose sum is σ = 34560000. Its totient is φ = 11569536.

The previous prime is 21450511. The next prime is 21450521. The reversal of 21450513 is 31505412.

It is not a de Polignac number, because 21450513 - 2¹ = 21450511 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 21450513.

It is not an unprimeable number, because it can be changed into a prime (21450511) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 42738 + ... + 43236.

It is an arithmetic number, because the mean of its divisors is an integer number (1080000).

Almost surely, 2^21450513 is an apocalyptic number.

21450513 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21450513 is a deficient number, since it is larger than the sum of its proper divisors (13109487).

21450513 is a wasteful number, since it uses less digits than its factorization.

21450513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 621.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 21450513 is about 4631.4698530812. The cubic root of 21450513 is about 277.8513818403.

Adding to 21450513 its reverse (31505412), we get a palindrome (52955925).

The spelling of 21450513 in words is "twenty-one million, four hundred fifty thousand, five hundred thirteen".