66400870 has 16 divisors (see below), whose sum is σ = 120240288. Its totient is φ = 26400640.

The previous prime is 66400849. The next prime is 66400889. The reversal of 66400870 is 7800466.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18211 + ... + 21550.

It is an arithmetic number, because the mean of its divisors is an integer number (7515018).

Almost surely, 2^66400870 is an apocalyptic number.

66400870 is a deficient number, since it is larger than the sum of its proper divisors (53839418).

66400870 is a wasteful number, since it uses less digits than its factorization.

66400870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39935.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 66400870 is about 8148.6728980859. The cubic root of 66400870 is about 404.9405389513.

The spelling of 66400870 in words is "sixty-six million, four hundred thousand, eight hundred seventy".