21794537 has 4 divisors (see below), whose sum is σ = 21807060. Its totient is φ = 21782016.

The previous prime is 21794533. The next prime is 21794543. The reversal of 21794537 is 73549712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16883881 + 4910656 = 4109^2 + 2216^2 .

It is a cyclic number.

It is not a de Polignac number, because 21794537 - 2² = 21794533 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 21794537.

It is not an unprimeable number, because it can be changed into a prime (21794533) 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 3 ways as a sum of consecutive naturals, for example, 3128 + ... + 7305.

It is an arithmetic number, because the mean of its divisors is an integer number (5451765).

Almost surely, 2^21794537 is an apocalyptic number.

It is an amenable number.

21794537 is a deficient number, since it is larger than the sum of its proper divisors (12523).

21794537 is a wasteful number, since it uses less digits than its factorization.

21794537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12522.

The product of its digits is 52920, while the sum is 38.

The square root of 21794537 is about 4668.4619522922. The cubic root of 21794537 is about 279.3289072929.

The spelling of 21794537 in words is "twenty-one million, seven hundred ninety-four thousand, five hundred thirty-seven".