32991640 has 64 divisors (see below), whose sum is σ = 81920160. Its totient is φ = 11857920.

The previous prime is 32991617. The next prime is 32991643. The reversal of 32991640 is 4619923.

It is a junction number, because it is equal to n+sod(n) for n = 32991596 and 32991605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (32991643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42294 + ... + 43066.

Almost surely, 2^32991640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 32991640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40960080).

32991640 is an abundant number, since it is smaller than the sum of its proper divisors (48928520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

32991640 is a wasteful number, since it uses less digits than its factorization.

32991640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 892 (or 888 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 32991640 is about 5743.8349558461. The cubic root of 32991640 is about 320.7263448666.

The spelling of 32991640 in words is "thirty-two million, nine hundred ninety-one thousand, six hundred forty".