21140145 has 24 divisors (see below), whose sum is σ = 39462696. Its totient is φ = 10407168.

The previous prime is 21140123. The next prime is 21140149. The reversal of 21140145 is 54104112.

It can be written as a sum of positive squares in 4 ways, for example, as 646416 + 20493729 = 804^2 + 4527^2 .

It is not a de Polignac number, because 21140145 - 2¹⁴ = 21123761 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21140149) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17484 + ... + 18653.

It is an arithmetic number, because the mean of its divisors is an integer number (1644279).

Almost surely, 2^21140145 is an apocalyptic number.

It is an amenable number.

21140145 is a deficient number, since it is larger than the sum of its proper divisors (18322551).

21140145 is a wasteful number, since it uses less digits than its factorization.

21140145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36161 (or 36158 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 21140145 is about 4597.8413413253. The cubic root of 21140145 is about 276.5047866740.

Adding to 21140145 its reverse (54104112), we get a palindrome (75244257).

The spelling of 21140145 in words is "twenty-one million, one hundred forty thousand, one hundred forty-five".