155663321 has 8 divisors (see below), whose sum is σ = 171497088. Its totient is φ = 140110000.

The previous prime is 155663317. The next prime is 155663327. The reversal of 155663321 is 123366551.

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 155663321 - 2² = 155663317 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155663327) 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, 68945 + ... + 71166.

It is an arithmetic number, because the mean of its divisors is an integer number (21437136).

Almost surely, 2^155663321 is an apocalyptic number.

155663321 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

155663321 is a deficient number, since it is larger than the sum of its proper divisors (15833767).

155663321 is a wasteful number, since it uses less digits than its factorization.

155663321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140223.

The product of its digits is 16200, while the sum is 32.

The square root of 155663321 is about 12476.5107702434. The cubic root of 155663321 is about 537.9337141884.

The spelling of 155663321 in words is "one hundred fifty-five million, six hundred sixty-three thousand, three hundred twenty-one".