155194993 has 2 divisors, whose sum is σ = 155194994. Its totient is φ = 155194992.

The previous prime is 155194939. The next prime is 155194999. The reversal of 155194993 is 399491551.

It is a happy number.

Together with previous prime (155194939) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80407089 + 74787904 = 8967^2 + 8648^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155194993 is a prime.

It is not a weakly prime, because it can be changed into another prime (155194999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77597496 + 77597497.

It is an arithmetic number, because the mean of its divisors is an integer number (77597497).

Almost surely, 2^155194993 is an apocalyptic number.

It is an amenable number.

155194993 is a deficient number, since it is larger than the sum of its proper divisors (1).

155194993 is an equidigital number, since it uses as much as digits as its factorization.

155194993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 218700, while the sum is 46.

The square root of 155194993 is about 12457.7282439456. The cubic root of 155194993 is about 537.3936972397.

The spelling of 155194993 in words is "one hundred fifty-five million, one hundred ninety-four thousand, nine hundred ninety-three".