21612045 has 64 divisors (see below), whose sum is σ = 43352064. Its totient is φ = 8951040.

The previous prime is 21612037. The next prime is 21612061. The reversal of 21612045 is 54021612.

It is not a de Polignac number, because 21612045 - 2³ = 21612037 is a prime.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 96804 + ... + 97026.

It is an arithmetic number, because the mean of its divisors is an integer number (677376).

Almost surely, 2^21612045 is an apocalyptic number.

It is an amenable number.

21612045 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

21612045 is a wasteful number, since it uses less digits than its factorization.

21612045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 21612045 is about 4648.8756705251. The cubic root of 21612045 is about 278.5470870062.

Adding to 21612045 its reverse (54021612), we get a palindrome (75633657).

The spelling of 21612045 in words is "twenty-one million, six hundred twelve thousand, forty-five".