66921782 has 4 divisors (see below), whose sum is σ = 100382676. Its totient is φ = 33460890.

The previous prime is 66921779. The next prime is 66921787. The reversal of 66921782 is 28712966.

It is a semiprime because it is the product of two primes.

It is a super-3 number, since 3×66921782³ (a number of 24 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66921787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16730444 + ... + 16730447.

It is an arithmetic number, because the mean of its divisors is an integer number (25095669).

Almost surely, 2^66921782 is an apocalyptic number.

66921782 is a deficient number, since it is larger than the sum of its proper divisors (33460894).

66921782 is a wasteful number, since it uses less digits than its factorization.

66921782 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33460893.

The product of its digits is 72576, while the sum is 41.

The square root of 66921782 is about 8180.5734517820. The cubic root of 66921782 is about 405.9966956787.

The spelling of 66921782 in words is "sixty-six million, nine hundred twenty-one thousand, seven hundred eighty-two".