155221793 has 4 divisors (see below), whose sum is σ = 156263700. Its totient is φ = 154179888.

The previous prime is 155221783. The next prime is 155221817. The reversal of 155221793 is 397122551.

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 19918369 + 135303424 = 4463^2 + 11632^2 .

It is a cyclic number.

It is not a de Polignac number, because 155221793 - 2¹² = 155217697 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (155221723) 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, 520730 + ... + 521027.

It is an arithmetic number, because the mean of its divisors is an integer number (39065925).

Almost surely, 2^155221793 is an apocalyptic number.

It is an amenable number.

155221793 is a deficient number, since it is larger than the sum of its proper divisors (1041907).

155221793 is a wasteful number, since it uses less digits than its factorization.

155221793 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1041906.

The product of its digits is 18900, while the sum is 35.

The square root of 155221793 is about 12458.8038350397. The cubic root of 155221793 is about 537.4246289124.

The spelling of 155221793 in words is "one hundred fifty-five million, two hundred twenty-one thousand, seven hundred ninety-three".