1539218081 has 2 divisors, whose sum is σ = 1539218082. Its totient is φ = 1539218080.

The previous prime is 1539218059. The next prime is 1539218099. The reversal of 1539218081 is 1808129351.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1537816225 + 1401856 = 39215^2 + 1184^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1539218081 is a prime.

It is a super-2 number, since 2×1539218081² = 4738384601754645122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1539218011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 769609040 + 769609041.

It is an arithmetic number, because the mean of its divisors is an integer number (769609041).

Almost surely, 2^1539218081 is an apocalyptic number.

It is an amenable number.

1539218081 is a deficient number, since it is larger than the sum of its proper divisors (1).

1539218081 is an equidigital number, since it uses as much as digits as its factorization.

1539218081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 38.

The square root of 1539218081 is about 39232.8699052211. The cubic root of 1539218081 is about 1154.6048712437.

The spelling of 1539218081 in words is "one billion, five hundred thirty-nine million, two hundred eighteen thousand, eighty-one".