221291263 has 4 divisors (see below), whose sum is σ = 222450048. Its totient is φ = 220132480.

The previous prime is 221291249. The next prime is 221291267. The reversal of 221291263 is 362192122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 362192122 = 2 ⋅181096061.

It is a cyclic number.

It is not a de Polignac number, because 221291263 - 2¹³ = 221283071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221291267) 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, 579106 + ... + 579487.

It is an arithmetic number, because the mean of its divisors is an integer number (55612512).

Almost surely, 2^221291263 is an apocalyptic number.

221291263 is a deficient number, since it is larger than the sum of its proper divisors (1158785).

221291263 is a wasteful number, since it uses less digits than its factorization.

221291263 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1158784.

The product of its digits is 2592, while the sum is 28.

The square root of 221291263 is about 14875.8617565504. The cubic root of 221291263 is about 604.8598477803.

The spelling of 221291263 in words is "two hundred twenty-one million, two hundred ninety-one thousand, two hundred sixty-three".