31201801 has 4 divisors (see below), whose sum is σ = 31213204. Its totient is φ = 31190400.

The previous prime is 31201787. The next prime is 31201811. The reversal of 31201801 is 10810213.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 10810213 = 2153 ⋅5021.

It can be written as a sum of positive squares in 2 ways, for example, as 17214201 + 13987600 = 4149^2 + 3740^2 .

It is a 3-Lehmer number, since φ(31201801) divides (31201801-1)³.

It is a cyclic number.

It is not a de Polignac number, because 31201801 - 2⁵ = 31201769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31201811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1141 + ... + 7981.

It is an arithmetic number, because the mean of its divisors is an integer number (7803301).

Almost surely, 2^31201801 is an apocalyptic number.

31201801 is the 4561-st pentagonal number.

It is an amenable number.

31201801 is a deficient number, since it is larger than the sum of its proper divisors (11403).

31201801 is an equidigital number, since it uses as much as digits as its factorization.

31201801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11402.

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 31201801 is about 5585.8572305421. The cubic root of 31201801 is about 314.8182406536.

The spelling of 31201801 in words is "thirty-one million, two hundred one thousand, eight hundred one".