66431772 has 96 divisors (see below), whose sum is σ = 189504000. Its totient is φ = 19958400.

The previous prime is 66431731. The next prime is 66431819. The reversal of 66431772 is 27713466.

66431772 is a `hidden beast` number, since 6 + 643 + 1 + 7 + 7 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

Its product of digits (42336) is a multiple of the sum of its prime factors (504).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 236272 + ... + 236552.

It is an arithmetic number, because the mean of its divisors is an integer number (1974000).

Almost surely, 2^66431772 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 66431772, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94752000).

66431772 is an abundant number, since it is smaller than the sum of its proper divisors (123072228).

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

66431772 is a wasteful number, since it uses less digits than its factorization.

66431772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 504 (or 496 counting only the distinct ones).

The product of its digits is 42336, while the sum is 36.

The square root of 66431772 is about 8150.5688145061. The cubic root of 66431772 is about 405.0033470231.

The spelling of 66431772 in words is "sixty-six million, four hundred thirty-one thousand, seven hundred seventy-two".