155721863 has 16 divisors (see below), whose sum is σ = 175653024. Its totient is φ = 136805760.

The previous prime is 155721833. The next prime is 155721883. The reversal of 155721863 is 368127551.

It is a cyclic number.

It is not a de Polignac number, because 155721863 - 2⁸ = 155721607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155721803) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 62681 + ... + 65117.

It is an arithmetic number, because the mean of its divisors is an integer number (10978314).

Almost surely, 2^155721863 is an apocalyptic number.

155721863 is a deficient number, since it is larger than the sum of its proper divisors (19931161).

155721863 is a wasteful number, since it uses less digits than its factorization.

155721863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2642.

The product of its digits is 50400, while the sum is 38.

The square root of 155721863 is about 12478.8566383303. The cubic root of 155721863 is about 538.0011412661.

The spelling of 155721863 in words is "one hundred fifty-five million, seven hundred twenty-one thousand, eight hundred sixty-three".