221379287 has 4 divisors (see below), whose sum is σ = 234401616. Its totient is φ = 208356960.

The previous prime is 221379281. The next prime is 221379293. The reversal of 221379287 is 782973122.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (221379281) and next prime (221379293).

It is a cyclic number.

It is not a de Polignac number, because 221379287 - 2⁸ = 221379031 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 (221379281) 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, 6511139 + ... + 6511172.

It is an arithmetic number, because the mean of its divisors is an integer number (58600404).

Almost surely, 2^221379287 is an apocalyptic number.

221379287 is a deficient number, since it is larger than the sum of its proper divisors (13022329).

221379287 is a wasteful number, since it uses less digits than its factorization.

221379287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13022328.

The product of its digits is 84672, while the sum is 41.

The square root of 221379287 is about 14878.8200809070. The cubic root of 221379287 is about 604.9400364038.

The spelling of 221379287 in words is "two hundred twenty-one million, three hundred seventy-nine thousand, two hundred eighty-seven".