32991681 has 4 divisors (see below), whose sum is σ = 43988912. Its totient is φ = 21994452.

The previous prime is 32991661. The next prime is 32991701. The reversal of 32991681 is 18619923.

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 (32991661) and next prime (32991701).

It is not a de Polignac number, because 32991681 - 2⁵ = 32991649 is a prime.

It is a super-3 number, since 3×32991681³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (32991661) 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, 5498611 + ... + 5498616.

It is an arithmetic number, because the mean of its divisors is an integer number (10997228).

Almost surely, 2^32991681 is an apocalyptic number.

It is an amenable number.

32991681 is a deficient number, since it is larger than the sum of its proper divisors (10997231).

32991681 is a wasteful number, since it uses less digits than its factorization.

32991681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10997230.

The product of its digits is 23328, while the sum is 39.

The square root of 32991681 is about 5743.8385248891. The cubic root of 32991681 is about 320.7264777262.

The spelling of 32991681 in words is "thirty-two million, nine hundred ninety-one thousand, six hundred eighty-one".