21947355 has 40 divisors (see below), whose sum is σ = 40214592. Its totient is φ = 11446272.

The previous prime is 21947339. The next prime is 21947363. The reversal of 21947355 is 55374912.

It is not a de Polignac number, because 21947355 - 2⁴ = 21947339 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 18459 + ... + 19611.

Almost surely, 2^21947355 is an apocalyptic number.

21947355 is a deficient number, since it is larger than the sum of its proper divisors (18267237).

21947355 is a wasteful number, since it uses less digits than its factorization.

21947355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1217 (or 1208 counting only the distinct ones).

The product of its digits is 37800, while the sum is 36.

The square root of 21947355 is about 4684.8004226434. The cubic root of 21947355 is about 279.9802494572.

It can be divided in two parts, 219 and 47355, that added together give a palindrome (47574).

The spelling of 21947355 in words is "twenty-one million, nine hundred forty-seven thousand, three hundred fifty-five".