21790347 has 8 divisors (see below), whose sum is σ = 29176320. Its totient is φ = 14465640.

The previous prime is 21790309. The next prime is 21790369. The reversal of 21790347 is 74309712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21790347 - 2⁸ = 21790091 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (21790387) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14479 + ... + 15912.

It is an arithmetic number, because the mean of its divisors is an integer number (3647040).

Almost surely, 2^21790347 is an apocalyptic number.

21790347 is a deficient number, since it is larger than the sum of its proper divisors (7385973).

21790347 is a wasteful number, since it uses less digits than its factorization.

21790347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30633.

The product of its (nonzero) digits is 10584, while the sum is 33.

The square root of 21790347 is about 4668.0131747886. The cubic root of 21790347 is about 279.3110058170.

The spelling of 21790347 in words is "twenty-one million, seven hundred ninety thousand, three hundred forty-seven".