66971390 has 16 divisors (see below), whose sum is σ = 126893520. Its totient is φ = 25378560.

The previous prime is 66971357. The next prime is 66971393. The reversal of 66971390 is 9317966.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66971393) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176051 + ... + 176430.

It is an arithmetic number, because the mean of its divisors is an integer number (7930845).

Almost surely, 2^66971390 is an apocalyptic number.

66971390 is a deficient number, since it is larger than the sum of its proper divisors (59922130).

66971390 is a wasteful number, since it uses less digits than its factorization.

66971390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352507.

The product of its (nonzero) digits is 61236, while the sum is 41.

The square root of 66971390 is about 8183.6049513646. The cubic root of 66971390 is about 406.0969904252.

The spelling of 66971390 in words is "sixty-six million, nine hundred seventy-one thousand, three hundred ninety".