21132545 has 16 divisors (see below), whose sum is σ = 29918208. Its totient is φ = 14022720.

The previous prime is 21132509. The next prime is 21132557. The reversal of 21132545 is 54523112.

It is not a de Polignac number, because 21132545 - 2⁶ = 21132481 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21132545.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8654 + ... + 10823.

It is an arithmetic number, because the mean of its divisors is an integer number (1869888).

Almost surely, 2^21132545 is an apocalyptic number.

It is an amenable number.

21132545 is a deficient number, since it is larger than the sum of its proper divisors (8785663).

21132545 is a wasteful number, since it uses less digits than its factorization.

21132545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19520.

The product of its digits is 1200, while the sum is 23.

The square root of 21132545 is about 4597.0147922320. The cubic root of 21132545 is about 276.4716476983.

Adding to 21132545 its reverse (54523112), we get a palindrome (75655657).

The spelling of 21132545 in words is "twenty-one million, one hundred thirty-two thousand, five hundred forty-five".