155560921 has 4 divisors (see below), whose sum is σ = 156206644. Its totient is φ = 154915200.

The previous prime is 155560859. The next prime is 155560927. The reversal of 155560921 is 129065551.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 131354521 + 24206400 = 11461^2 + 4920^2 .

It is a cyclic number.

It is not a de Polignac number, because 155560921 - 2⁹ = 155560409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155560927) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 322500 + ... + 322981.

It is an arithmetic number, because the mean of its divisors is an integer number (39051661).

Almost surely, 2^155560921 is an apocalyptic number.

It is an amenable number.

155560921 is a deficient number, since it is larger than the sum of its proper divisors (645723).

155560921 is an equidigital number, since it uses as much as digits as its factorization.

155560921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645722.

The product of its (nonzero) digits is 13500, while the sum is 34.

The square root of 155560921 is about 12472.4063836936. The cubic root of 155560921 is about 537.8157320050.

The spelling of 155560921 in words is "one hundred fifty-five million, five hundred sixty thousand, nine hundred twenty-one".