155981972 has 6 divisors (see below), whose sum is σ = 272968458. Its totient is φ = 77990984.

The previous prime is 155981957. The next prime is 155981977. The reversal of 155981972 is 279189551.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 86192656 + 69789316 = 9284^2 + 8354^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155981977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19497743 + ... + 19497750.

It is an arithmetic number, because the mean of its divisors is an integer number (45494743).

Almost surely, 2^155981972 is an apocalyptic number.

It is an amenable number.

155981972 is a deficient number, since it is larger than the sum of its proper divisors (116986486).

155981972 is a wasteful number, since it uses less digits than its factorization.

155981972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38995497 (or 38995495 counting only the distinct ones).

The product of its digits is 226800, while the sum is 47.

The square root of 155981972 is about 12489.2742783558. The cubic root of 155981972 is about 538.3005235387.

The spelling of 155981972 in words is "one hundred fifty-five million, nine hundred eighty-one thousand, nine hundred seventy-two".