21140945 has 16 divisors (see below), whose sum is σ = 30699648. Its totient is φ = 13643520.

The previous prime is 21140921. The next prime is 21140957. The reversal of 21140945 is 54904112.

It is not a de Polignac number, because 21140945 - 2⁸ = 21140689 is a prime.

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 15 ways as a sum of consecutive naturals, for example, 17171 + ... + 18360.

It is an arithmetic number, because the mean of its divisors is an integer number (1918728).

Almost surely, 2^21140945 is an apocalyptic number.

It is an amenable number.

21140945 is a deficient number, since it is larger than the sum of its proper divisors (9558703).

21140945 is a wasteful number, since it uses less digits than its factorization.

21140945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35560.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 21140945 is about 4597.9283378496. The cubic root of 21140945 is about 276.5082745252.

The spelling of 21140945 in words is "twenty-one million, one hundred forty thousand, nine hundred forty-five".