71801581 has 4 divisors (see below), whose sum is σ = 71824032. Its totient is φ = 71779132.

The previous prime is 71801579. The next prime is 71801603. The reversal of 71801581 is 18510817.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18510817 = 13 ⋅1423909.

It is a cyclic number.

It is not a de Polignac number, because 71801581 - 2¹ = 71801579 is a prime.

It is a super-2 number, since 2×71801581² = 10310934068199122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71801501) 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, 5431 + ... + 13156.

It is an arithmetic number, because the mean of its divisors is an integer number (17956008).

Almost surely, 2^71801581 is an apocalyptic number.

It is an amenable number.

71801581 is a deficient number, since it is larger than the sum of its proper divisors (22451).

71801581 is a wasteful number, since it uses less digits than its factorization.

71801581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22450.

The product of its (nonzero) digits is 2240, while the sum is 31.

The square root of 71801581 is about 8473.5813561917. The cubic root of 71801581 is about 415.6342573249.

The spelling of 71801581 in words is "seventy-one million, eight hundred one thousand, five hundred eighty-one".