21332451 has 16 divisors (see below), whose sum is σ = 32626944. Its totient is φ = 12144864.

The previous prime is 21332419. The next prime is 21332471. The reversal of 21332451 is 15423312.

It is not a de Polignac number, because 21332451 - 2⁵ = 21332419 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (21332401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4420 + ... + 7886.

It is an arithmetic number, because the mean of its divisors is an integer number (2039184).

Almost surely, 2^21332451 is an apocalyptic number.

21332451 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21332451 is a deficient number, since it is larger than the sum of its proper divisors (11294493).

21332451 is a wasteful number, since it uses less digits than its factorization.

21332451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3770.

The product of its digits is 720, while the sum is 21.

The square root of 21332451 is about 4618.7066371442. The cubic root of 21332451 is about 277.3406860890.

Adding to 21332451 its reverse (15423312), we get a palindrome (36755763).

The spelling of 21332451 in words is "twenty-one million, three hundred thirty-two thousand, four hundred fifty-one".