221947897 has 4 divisors (see below), whose sum is σ = 227109520. Its totient is φ = 216786276.

The previous prime is 221947889. The next prime is 221947927. The reversal of 221947897 is 798749122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221947897 - 2³ = 221947889 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 221947897.

It is not an unprimeable number, because it can be changed into a prime (221947807) 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, 2580747 + ... + 2580832.

It is an arithmetic number, because the mean of its divisors is an integer number (56777380).

Almost surely, 2^221947897 is an apocalyptic number.

It is an amenable number.

221947897 is a deficient number, since it is larger than the sum of its proper divisors (5161623).

221947897 is an equidigital number, since it uses as much as digits as its factorization.

221947897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5161622.

The product of its digits is 508032, while the sum is 49.

The square root of 221947897 is about 14897.9158609518. The cubic root of 221947897 is about 605.4575206421.

The spelling of 221947897 in words is "two hundred twenty-one million, nine hundred forty-seven thousand, eight hundred ninety-seven".