220155781 has 2 divisors, whose sum is σ = 220155782. Its totient is φ = 220155780.

The previous prime is 220155779. The next prime is 220155823. The reversal of 220155781 is 187551022.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 158533281 + 61622500 = 12591^2 + 7850^2 .

It is a cyclic number.

It is not a de Polignac number, because 220155781 - 2¹ = 220155779 is a prime.

It is a super-2 number, since 2×220155781² = 96937135815439922, which contains 22 as substring.

Together with 220155779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (220155731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110077890 + 110077891.

It is an arithmetic number, because the mean of its divisors is an integer number (110077891).

Almost surely, 2^220155781 is an apocalyptic number.

It is an amenable number.

220155781 is a deficient number, since it is larger than the sum of its proper divisors (1).

220155781 is an equidigital number, since it uses as much as digits as its factorization.

220155781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5600, while the sum is 31.

The square root of 220155781 is about 14837.6474213401. The cubic root of 220155781 is about 603.8235280027.

The spelling of 220155781 in words is "two hundred twenty million, one hundred fifty-five thousand, seven hundred eighty-one".