155772720 has 140 divisors (see below), whose sum is σ = 543212256. Its totient is φ = 41523840.

The previous prime is 155772709. The next prime is 155772761. The reversal of 155772720 is 27277551.

155772720 is a `hidden beast` number, since 15 + 577 + 2 + 72 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 56985 + ... + 59655.

Almost surely, 2^155772720 is an apocalyptic number.

155772720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 155772720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (271606128).

155772720 is an abundant number, since it is smaller than the sum of its proper divisors (387439536).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

155772720 is an equidigital number, since it uses as much as digits as its factorization.

155772720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2702 (or 2681 counting only the distinct ones).

The product of its (nonzero) digits is 34300, while the sum is 36.

The square root of 155772720 is about 12480.8941987343. The cubic root of 155772720 is about 538.0597032549.

The spelling of 155772720 in words is "one hundred fifty-five million, seven hundred seventy-two thousand, seven hundred twenty".