21347573 has 6 divisors (see below), whose sum is σ = 23116194. Its totient is φ = 19705296.

The previous prime is 21347569. The next prime is 21347581. The reversal of 21347573 is 37574312.

It can be written as a sum of positive squares in 3 ways, for example, as 1214404 + 20133169 = 1102^2 + 4487^2 .

It is not a de Polignac number, because 21347573 - 2² = 21347569 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21347533) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 62990 + ... + 63327.

It is an arithmetic number, because the mean of its divisors is an integer number (3852699).

Almost surely, 2^21347573 is an apocalyptic number.

It is an amenable number.

21347573 is a deficient number, since it is larger than the sum of its proper divisors (1768621).

21347573 is a wasteful number, since it uses less digits than its factorization.

21347573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126343 (or 126330 counting only the distinct ones).

The product of its digits is 17640, while the sum is 32.

The square root of 21347573 is about 4620.3433855072. The cubic root of 21347573 is about 277.4062037246.

The spelling of 21347573 in words is "twenty-one million, three hundred forty-seven thousand, five hundred seventy-three".