163801581 has 4 divisors (see below), whose sum is σ = 218402112. Its totient is φ = 109201052.

The previous prime is 163801571. The next prime is 163801591. The reversal of 163801581 is 185108361.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (163801571) and next prime (163801591).

It is a cyclic number.

It is not a de Polignac number, because 163801581 - 2⁷ = 163801453 is a prime.

It is a super-2 number, since 2×163801581² = 53661915876199122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (163801501) 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, 27300261 + ... + 27300266.

It is an arithmetic number, because the mean of its divisors is an integer number (54600528).

Almost surely, 2^163801581 is an apocalyptic number.

It is an amenable number.

163801581 is a deficient number, since it is larger than the sum of its proper divisors (54600531).

163801581 is an equidigital number, since it uses as much as digits as its factorization.

163801581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54600530.

The product of its (nonzero) digits is 5760, while the sum is 33.

The square root of 163801581 is about 12798.4991698246. The cubic root of 163801581 is about 547.1495290423.

The spelling of 163801581 in words is "one hundred sixty-three million, eight hundred one thousand, five hundred eighty-one".