161802391 has 4 divisors (see below), whose sum is σ = 163373392. Its totient is φ = 160231392.

The previous prime is 161802371. The next prime is 161802449. The reversal of 161802391 is 193208161.

161802391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 161802391 - 2¹¹ = 161800343 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 (161802331) 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, 785346 + ... + 785551.

It is an arithmetic number, because the mean of its divisors is an integer number (40843348).

Almost surely, 2^161802391 is an apocalyptic number.

161802391 is a deficient number, since it is larger than the sum of its proper divisors (1571001).

161802391 is a wasteful number, since it uses less digits than its factorization.

161802391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1571000.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 161802391 is about 12720.1568779634. The cubic root of 161802391 is about 544.9144337231.

The spelling of 161802391 in words is "one hundred sixty-one million, eight hundred two thousand, three hundred ninety-one".