21132345 has 32 divisors (see below), whose sum is σ = 36634752. Its totient is φ = 10340352.

The previous prime is 21132341. The next prime is 21132383. The reversal of 21132345 is 54323112.

It is not a de Polignac number, because 21132345 - 2² = 21132341 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21132341) 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 31 ways as a sum of consecutive naturals, for example, 59689 + ... + 60041.

It is an arithmetic number, because the mean of its divisors is an integer number (1144836).

Almost surely, 2^21132345 is an apocalyptic number.

It is an amenable number.

21132345 is a deficient number, since it is larger than the sum of its proper divisors (15502407).

21132345 is a wasteful number, since it uses less digits than its factorization.

21132345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 681.

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

The square root of 21132345 is about 4596.9930389332. The cubic root of 21132345 is about 276.4707755127.

Adding to 21132345 its reverse (54323112), we get a palindrome (75455457).

The spelling of 21132345 in words is "twenty-one million, one hundred thirty-two thousand, three hundred forty-five".