155121261 has 16 divisors (see below), whose sum is σ = 214608960. Its totient is φ = 99545600.

The previous prime is 155121251. The next prime is 155121283. The reversal of 155121261 is 162121551.

It is a cyclic number.

It is not a de Polignac number, because 155121261 - 2⁷ = 155121133 is a prime.

It is a super-2 number, since 2×155121261² = 48125211228460242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155121251) 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, 28186 + ... + 33236.

It is an arithmetic number, because the mean of its divisors is an integer number (13413060).

Almost surely, 2^155121261 is an apocalyptic number.

It is an amenable number.

155121261 is a deficient number, since it is larger than the sum of its proper divisors (59487699).

155121261 is a wasteful number, since it uses less digits than its factorization.

155121261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5436.

The product of its digits is 600, while the sum is 24.

The square root of 155121261 is about 12454.7686048357. The cubic root of 155121261 is about 537.3085798274.

The spelling of 155121261 in words is "one hundred fifty-five million, one hundred twenty-one thousand, two hundred sixty-one".