155401225561 has 2 divisors, whose sum is σ = 155401225562. Its totient is φ = 155401225560.

The previous prime is 155401225541. The next prime is 155401225669. The reversal of 155401225561 is 165522104551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 112388539536 + 43012686025 = 335244^2 + 207395^2 .

It is an emirp because it is prime and its reverse (165522104551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 155401225561 - 2¹¹ = 155401223513 is a prime.

It is a super-3 number, since 3×155401225561³ (a number of 35 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 155401225561.

It is not a weakly prime, because it can be changed into another prime (155401225501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77700612780 + 77700612781.

It is an arithmetic number, because the mean of its divisors is an integer number (77700612781).

Almost surely, 2^155401225561 is an apocalyptic number.

It is an amenable number.

155401225561 is a deficient number, since it is larger than the sum of its proper divisors (1).

155401225561 is an equidigital number, since it uses as much as digits as its factorization.

155401225561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60000, while the sum is 37.

The spelling of 155401225561 in words is "one hundred fifty-five billion, four hundred one million, two hundred twenty-five thousand, five hundred sixty-one".