66839649 has 16 divisors (see below), whose sum is σ = 91765440. Its totient is φ = 43243200.

The previous prime is 66839621. The next prime is 66839657. The reversal of 66839649 is 94693866.

It is not a de Polignac number, because 66839649 - 2²¹ = 64742497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66839249) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 77382 + ... + 78240.

It is an arithmetic number, because the mean of its divisors is an integer number (5735340).

Almost surely, 2^66839649 is an apocalyptic number.

It is an amenable number.

66839649 is a deficient number, since it is larger than the sum of its proper divisors (24925791).

66839649 is a wasteful number, since it uses less digits than its factorization.

66839649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1600.

The product of its digits is 1679616, while the sum is 51.

The square root of 66839649 is about 8175.5519079754. The cubic root of 66839649 is about 405.8305346440.

The spelling of 66839649 in words is "sixty-six million, eight hundred thirty-nine thousand, six hundred forty-nine".