66776390 has 16 divisors (see below), whose sum is σ = 120636432. Its totient is φ = 26613024.

The previous prime is 66776329. The next prime is 66776399. The reversal of 66776390 is 9367766.

It is a super-2 number, since 2×66776390² = 8918172522864200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66776399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9284 + ... + 14823.

It is an arithmetic number, because the mean of its divisors is an integer number (7539777).

Almost surely, 2^66776390 is an apocalyptic number.

66776390 is a deficient number, since it is larger than the sum of its proper divisors (53860042).

66776390 is a wasteful number, since it uses less digits than its factorization.

66776390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24391.

The product of its (nonzero) digits is 285768, while the sum is 44.

The square root of 66776390 is about 8171.6822013585. The cubic root of 66776390 is about 405.7024642672.

Subtracting from 66776390 its sum of digits (44), we obtain a triangular number (66776346 = T₁₁₅₅₆).

The spelling of 66776390 in words is "sixty-six million, seven hundred seventy-six thousand, three hundred ninety".