228501981 has 24 divisors (see below), whose sum is σ = 350980344. Its totient is φ = 142755840.

The previous prime is 228501971. The next prime is 228501983. The reversal of 228501981 is 189105822.

It can be written as a sum of positive squares in 4 ways, for example, as 76842756 + 151659225 = 8766^2 + 12315^2 .

It is not a de Polignac number, because 228501981 - 2⁷ = 228501853 is a prime.

It is a super-2 number, since 2×228501981² = 104426310641848722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (228501983) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33775 + ... + 39971.

It is an arithmetic number, because the mean of its divisors is an integer number (14624181).

Almost surely, 2^228501981 is an apocalyptic number.

It is an amenable number.

228501981 is a deficient number, since it is larger than the sum of its proper divisors (122478363).

228501981 is a wasteful number, since it uses less digits than its factorization.

228501981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6461 (or 6458 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 228501981 is about 15116.2819833450. The cubic root of 228501981 is about 611.3594878333.

The spelling of 228501981 in words is "two hundred twenty-eight million, five hundred one thousand, nine hundred eighty-one".