66974440 has 96 divisors (see below), whose sum is σ = 169543080. Its totient is φ = 23652864.

The previous prime is 66974437. The next prime is 66974447. The reversal of 66974440 is 4447966.

66974440 = T₂₇₉ + T₂₈₀ + ... + T₇₅₀.

It can be written as a sum of positive squares in 4 ways, for example, as 55264356 + 11710084 = 7434^2 + 3422^2 .

It is a super-2 number, since 2×66974440² = 8971151226627200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 66974393 and 66974402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66974447) 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, 1135131 + ... + 1135189.

Almost surely, 2^66974440 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 66974440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84771540).

66974440 is an abundant number, since it is smaller than the sum of its proper divisors (102568640).

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

66974440 is a wasteful number, since it uses less digits than its factorization.

66974440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179 (or 116 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 40.

The square root of 66974440 is about 8183.7912974367. The cubic root of 66974440 is about 406.1031551323.

The spelling of 66974440 in words is "sixty-six million, nine hundred seventy-four thousand, four hundred forty".