21194523 has 24 divisors (see below), whose sum is σ = 36511488. Its totient is φ = 11583792.

The previous prime is 21194513. The next prime is 21194527. The reversal of 21194523 is 32549112.

It is not a de Polignac number, because 21194523 - 2⁴ = 21194507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21194527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5865 + ... + 8762.

It is an arithmetic number, because the mean of its divisors is an integer number (1521312).

Almost surely, 2^21194523 is an apocalyptic number.

21194523 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21194523 is a deficient number, since it is larger than the sum of its proper divisors (15316965).

21194523 is a wasteful number, since it uses less digits than its factorization.

21194523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14663 (or 14660 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 21194523 is about 4603.7509706760. The cubic root of 21194523 is about 276.7416646408.

The spelling of 21194523 in words is "twenty-one million, one hundred ninety-four thousand, five hundred twenty-three".