99966640 has 40 divisors (see below), whose sum is σ = 232842240. Its totient is φ = 39914496.

The previous prime is 99966631. The next prime is 99966673. The reversal of 99966640 is 4666999.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×99966640² = 19986658225779200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (49) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 10.

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, 77521 + ... + 78799.

It is an arithmetic number, because the mean of its divisors is an integer number (5821056).

Almost surely, 2^99966640 is an apocalyptic number.

It is an amenable number.

99966640 is an abundant number, since it is smaller than the sum of its proper divisors (132875600).

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

99966640 is a wasteful number, since it uses less digits than its factorization.

99966640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2269 (or 2263 counting only the distinct ones).

The product of its (nonzero) digits is 629856, while the sum is 49.

The square root of 99966640 is about 9998.3318608656. The cubic root of 99966640 is about 464.1072631529.

It can be divided in two parts, 9 and 9966640, that added together give a square (9966649 = 3157²).

The spelling of 99966640 in words is "ninety-nine million, nine hundred sixty-six thousand, six hundred forty".