66641616 has 50 divisors (see below), whose sum is σ = 192883922. Its totient is φ = 22213440.

The previous prime is 66641609. The next prime is 66641639. The reversal of 66641616 is 61614666.

It can be written as a sum of positive squares in only one way, i.e., 59351616 + 7290000 = 7704^2 + 2700^2 .

It is a super-2 number, since 2×66641616² = 8882209966182912, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 24415 + ... + 27006.

Almost surely, 2^66641616 is an apocalyptic number.

It is an amenable number.

66641616 is an abundant number, since it is smaller than the sum of its proper divisors (126242306).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66641616 is a wasteful number, since it uses less digits than its factorization.

66641616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51441 (or 51426 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 66641616 is about 8163.4316313668. The cubic root of 66641616 is about 405.4293389373.

The spelling of 66641616 in words is "sixty-six million, six hundred forty-one thousand, six hundred sixteen".