221077391 has 2 divisors, whose sum is σ = 221077392. Its totient is φ = 221077390.

The previous prime is 221077379. The next prime is 221077427. The reversal of 221077391 is 193770122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221077391 - 2¹⁴ = 221061007 is a prime.

It is a super-2 number, since 2×221077391² = 97750425622733762, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221077891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110538695 + 110538696.

It is an arithmetic number, because the mean of its divisors is an integer number (110538696).

Almost surely, 2^221077391 is an apocalyptic number.

221077391 is a deficient number, since it is larger than the sum of its proper divisors (1).

221077391 is an equidigital number, since it uses as much as digits as its factorization.

221077391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5292, while the sum is 32.

The square root of 221077391 is about 14868.6714604903. The cubic root of 221077391 is about 604.6649247617.

The spelling of 221077391 in words is "two hundred twenty-one million, seventy-seven thousand, three hundred ninety-one".