21450507 has 16 divisors (see below), whose sum is σ = 31519488. Its totient is φ = 12892320.

The previous prime is 21450493. The next prime is 21450509. The reversal of 21450507 is 70505412.

It is not a de Polignac number, because 21450507 - 2¹⁴ = 21434123 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21450509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4719 + ... + 8072.

It is an arithmetic number, because the mean of its divisors is an integer number (1969968).

Almost surely, 2^21450507 is an apocalyptic number.

21450507 is a deficient number, since it is larger than the sum of its proper divisors (10068981).

21450507 is a wasteful number, since it uses less digits than its factorization.

21450507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12850.

The product of its (nonzero) digits is 1400, while the sum is 24.

The square root of 21450507 is about 4631.4692053386. The cubic root of 21450507 is about 277.8513559340.

Adding to 21450507 its reverse (70505412), we get a palindrome (91955919).

It can be divided in two parts, 214 and 50507, that added together give a triangular number (50721 = T₃₁₈).

The spelling of 21450507 in words is "twenty-one million, four hundred fifty thousand, five hundred seven".