1228739581 has 2 divisors, whose sum is σ = 1228739582. Its totient is φ = 1228739580.

The previous prime is 1228739579. The next prime is 1228739641. The reversal of 1228739581 is 1859378221.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1160015481 + 68724100 = 34059^2 + 8290^2 .

It is a cyclic number.

It is not a de Polignac number, because 1228739581 - 2¹ = 1228739579 is a prime.

It is a super-2 number, since 2×1228739581² = 3019601915832111122, which contains 22 as substring.

Together with 1228739579, 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 (1228739081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 614369790 + 614369791.

It is an arithmetic number, because the mean of its divisors is an integer number (614369791).

Almost surely, 2^1228739581 is an apocalyptic number.

It is an amenable number.

1228739581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1228739581 is an equidigital number, since it uses as much as digits as its factorization.

1228739581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 241920, while the sum is 46.

The square root of 1228739581 is about 35053.3818767890. The cubic root of 1228739581 is about 1071.0751649525.

The spelling of 1228739581 in words is "one billion, two hundred twenty-eight million, seven hundred thirty-nine thousand, five hundred eighty-one".