66581632 has 32 divisors (see below), whose sum is σ = 142849980. Its totient is φ = 30729216.

The previous prime is 66581623. The next prime is 66581633. The reversal of 66581632 is 23618566.

It can be written as a sum of positive squares in 2 ways, for example, as 63107136 + 3474496 = 7944^2 + 1864^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×66581632² = 8866227439566848, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66581591 and 66581600.

It is not an unprimeable number, because it can be changed into a prime (66581633) 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, 18343 + ... + 21670.

Almost surely, 2^66581632 is an apocalyptic number.

It is an amenable number.

66581632 is an abundant number, since it is smaller than the sum of its proper divisors (76268348).

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

66581632 is a wasteful number, since it uses less digits than its factorization.

66581632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40040 (or 40028 counting only the distinct ones).

The product of its digits is 51840, while the sum is 37.

The square root of 66581632 is about 8159.7568591227. The cubic root of 66581632 is about 405.3076603469.

The spelling of 66581632 in words is "sixty-six million, five hundred eighty-one thousand, six hundred thirty-two".