155551997 has 2 divisors, whose sum is σ = 155551998. Its totient is φ = 155551996.

The previous prime is 155551973. The next prime is 155552011. The reversal of 155551997 is 799155551.

It is a happy number.

155551997 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 144336196 + 11215801 = 12014^2 + 3349^2 .

It is a cyclic number.

It is not a de Polignac number, because 155551997 - 2⁶ = 155551933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155251997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77775998 + 77775999.

It is an arithmetic number, because the mean of its divisors is an integer number (77775999).

Almost surely, 2^155551997 is an apocalyptic number.

It is an amenable number.

155551997 is a deficient number, since it is larger than the sum of its proper divisors (1).

155551997 is an equidigital number, since it uses as much as digits as its factorization.

155551997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 354375, while the sum is 47.

The square root of 155551997 is about 12472.0486288340. The cubic root of 155551997 is about 537.8054475897.

The spelling of 155551997 in words is "one hundred fifty-five million, five hundred fifty-one thousand, nine hundred ninety-seven".