155061981 has 12 divisors (see below), whose sum is σ = 237153852. Its totient is φ = 97293696.

The previous prime is 155061979. The next prime is 155061989. The reversal of 155061981 is 189160551.

It can be written as a sum of positive squares in 2 ways, for example, as 45441081 + 109620900 = 6741^2 + 10470^2 .

It is not a de Polignac number, because 155061981 - 2¹ = 155061979 is a prime.

It is a super-2 number, since 2×155061981² = 48088435903288722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155061989) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 506586 + ... + 506891.

It is an arithmetic number, because the mean of its divisors is an integer number (19762821).

Almost surely, 2^155061981 is an apocalyptic number.

It is an amenable number.

155061981 is a deficient number, since it is larger than the sum of its proper divisors (82091871).

155061981 is a wasteful number, since it uses less digits than its factorization.

155061981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1013500 (or 1013497 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 36.

The square root of 155061981 is about 12452.3885660543. The cubic root of 155061981 is about 537.2401264754.

The spelling of 155061981 in words is "one hundred fifty-five million, sixty-one thousand, nine hundred eighty-one".