21355671 has 8 divisors (see below), whose sum is σ = 28514160. Its totient is φ = 14217152.

The previous prime is 21355669. The next prime is 21355679. The reversal of 21355671 is 17655312.

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

It is a cyclic number.

It is not a de Polignac number, because 21355671 - 2¹ = 21355669 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21355679) 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, 2286 + ... + 6923.

It is an arithmetic number, because the mean of its divisors is an integer number (3564270).

Almost surely, 2^21355671 is an apocalyptic number.

21355671 is a deficient number, since it is larger than the sum of its proper divisors (7158489).

21355671 is an equidigital number, since it uses as much as digits as its factorization.

21355671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9985.

The product of its digits is 6300, while the sum is 30.

The square root of 21355671 is about 4621.2196442065. The cubic root of 21355671 is about 277.4412764304.

The spelling of 21355671 in words is "twenty-one million, three hundred fifty-five thousand, six hundred seventy-one".