155515515551 has 16 divisors (see below), whose sum is σ = 179736923808. Its totient is φ = 132984345600.

The previous prime is 155515515503. The next prime is 155515515599.

155515515551 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (155515515503) and next prime (155515515599).

It is a cyclic number.

It is not a de Polignac number, because 155515515551 - 2²² = 155511321247 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155515515251) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 84131 + ... + 564011.

It is an arithmetic number, because the mean of its divisors is an integer number (11233557738).

Almost surely, 2^155515515551 is an apocalyptic number.

155515515551 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

155515515551 is a deficient number, since it is larger than the sum of its proper divisors (24221408257).

155515515551 is a wasteful number, since it uses less digits than its factorization.

155515515551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481642.

The product of its digits is 390625, while the sum is 44.

The spelling of 155515515551 in words is "one hundred fifty-five billion, five hundred fifteen million, five hundred fifteen thousand, five hundred fifty-one".