66031780 has 48 divisors (see below), whose sum is σ = 141903216. Its totient is φ = 25804800.

The previous prime is 66031739. The next prime is 66031787. The reversal of 66031780 is 8713066.

It can be written as a sum of positive squares in 8 ways, for example, as 389376 + 65642404 = 624^2 + 8102^2 .

It is not an unprimeable number, because it can be changed into a prime (66031787) 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, 195772 + ... + 196108.

It is an arithmetic number, because the mean of its divisors is an integer number (2956317).

Almost surely, 2^66031780 is an apocalyptic number.

It is an amenable number.

66031780 is an abundant number, since it is smaller than the sum of its proper divisors (75871436).

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

66031780 is a wasteful number, since it uses less digits than its factorization.

66031780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544 (or 542 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 66031780 is about 8125.9940930326. The cubic root of 66031780 is about 404.1888555974.

The spelling of 66031780 in words is "sixty-six million, thirty-one thousand, seven hundred eighty".