99961681 has 8 divisors (see below), whose sum is σ = 101651328. Its totient is φ = 98280000.

The previous prime is 99961663. The next prime is 99961699. The reversal of 99961681 is 18616999.

It is an interprime number because it is at equal distance from previous prime (99961663) and next prime (99961699).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 4-Lehmer number, since φ(99961681) divides (99961681-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 99961681 - 2⁷ = 99961553 is a prime.

It is a super-2 number, since 2×99961681² = 19984675336691522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99931681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26716 + ... + 30226.

It is an arithmetic number, because the mean of its divisors is an integer number (12706416).

Almost surely, 2^99961681 is an apocalyptic number.

It is an amenable number.

99961681 is a deficient number, since it is larger than the sum of its proper divisors (1689647).

99961681 is a wasteful number, since it uses less digits than its factorization.

99961681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3983.

The product of its digits is 209952, while the sum is 49.

The square root of 99961681 is about 9998.0838664216. The cubic root of 99961681 is about 464.0995887728.

The spelling of 99961681 in words is "ninety-nine million, nine hundred sixty-one thousand, six hundred eighty-one".