66153978 has 48 divisors (see below), whose sum is σ = 157154400. Its totient is φ = 19945440.

The previous prime is 66153977. The next prime is 66154001. The reversal of 66153978 is 87935166.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (66153973) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44613 + ... + 46071.

It is an arithmetic number, because the mean of its divisors is an integer number (3274050).

Almost surely, 2^66153978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66153978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78577200).

66153978 is an abundant number, since it is smaller than the sum of its proper divisors (91000422).

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

66153978 is a wasteful number, since it uses less digits than its factorization.

66153978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1707 (or 1704 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 66153978 is about 8133.5095745932. The cubic root of 66153978 is about 404.4380317439.

The spelling of 66153978 in words is "sixty-six million, one hundred fifty-three thousand, nine hundred seventy-eight".