221447431 has 2 divisors, whose sum is σ = 221447432. Its totient is φ = 221447430.

The previous prime is 221447357. The next prime is 221447441. The reversal of 221447431 is 134744122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221447431 - 2¹⁵ = 221414663 is a prime.

It is a super-2 number, since 2×221447431² = 98077929392999522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 221447431.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221447441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110723715 + 110723716.

It is an arithmetic number, because the mean of its divisors is an integer number (110723716).

Almost surely, 2^221447431 is an apocalyptic number.

221447431 is a deficient number, since it is larger than the sum of its proper divisors (1).

221447431 is an equidigital number, since it uses as much as digits as its factorization.

221447431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 28.

The square root of 221447431 is about 14881.1098712428. The cubic root of 221447431 is about 605.0021000314.

The spelling of 221447431 in words is "two hundred twenty-one million, four hundred forty-seven thousand, four hundred thirty-one".