21370347 has 6 divisors (see below), whose sum is σ = 30868292. Its totient is φ = 14246892.

The previous prime is 21370339. The next prime is 21370357. The reversal of 21370347 is 74307312.

It is not a de Polignac number, because 21370347 - 2³ = 21370339 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 21370347.

It is not an unprimeable number, because it can be changed into a prime (21370357) 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 5 ways as a sum of consecutive naturals, for example, 1187233 + ... + 1187250.

Almost surely, 2^21370347 is an apocalyptic number.

21370347 is a deficient number, since it is larger than the sum of its proper divisors (9497945).

21370347 is a wasteful number, since it uses less digits than its factorization.

21370347 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2374489 (or 2374486 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 27.

The square root of 21370347 is about 4622.8072639901. The cubic root of 21370347 is about 277.5048160839.

Adding to 21370347 its reverse (74307312), we get a palindrome (95677659).

The spelling of 21370347 in words is "twenty-one million, three hundred seventy thousand, three hundred forty-seven".