21730367 has 4 divisors (see below), whose sum is σ = 22479720. Its totient is φ = 20981016.

The previous prime is 21730363. The next prime is 21730391. The reversal of 21730367 is 76303712.

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

It is a cyclic number.

It is not a de Polignac number, because 21730367 - 2² = 21730363 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 749323 = 21730367 / (2 + 1 + 7 + 3 + 0 + 3 + 6 + 7).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21730363) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 374633 + ... + 374690.

It is an arithmetic number, because the mean of its divisors is an integer number (5619930).

Almost surely, 2^21730367 is an apocalyptic number.

21730367 is a deficient number, since it is larger than the sum of its proper divisors (749353).

21730367 is an equidigital number, since it uses as much as digits as its factorization.

21730367 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 749352.

The product of its (nonzero) digits is 5292, while the sum is 29.

The square root of 21730367 is about 4661.5841727893. The cubic root of 21730367 is about 279.0544936230.

The spelling of 21730367 in words is "twenty-one million, seven hundred thirty thousand, three hundred sixty-seven".