155661553 has 8 divisors (see below), whose sum is σ = 160208000. Its totient is φ = 151133040.

The previous prime is 155661551. The next prime is 155661557. The reversal of 155661553 is 355166551.

155661553 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 155661553 - 2¹ = 155661551 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155661551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14248 + ... + 22678.

It is an arithmetic number, because the mean of its divisors is an integer number (20026000).

Almost surely, 2^155661553 is an apocalyptic number.

It is an amenable number.

155661553 is a deficient number, since it is larger than the sum of its proper divisors (4546447).

155661553 is an equidigital number, since it uses as much as digits as its factorization.

155661553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8967.

The product of its digits is 67500, while the sum is 37.

The square root of 155661553 is about 12476.4399168994. The cubic root of 155661553 is about 537.9316775913.

The spelling of 155661553 in words is "one hundred fifty-five million, six hundred sixty-one thousand, five hundred fifty-three".