9961661507 has 4 divisors (see below), whose sum is σ = 11384756016. Its totient is φ = 8538567000.

The previous prime is 9961661503. The next prime is 9961661519. The reversal of 9961661507 is 7051661699.

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

It is a cyclic number.

It is not a de Polignac number, because 9961661507 - 2² = 9961661503 is a prime.

It is a super-2 number, since 2×9961661507² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9961661503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 711547244 + ... + 711547257.

It is an arithmetic number, because the mean of its divisors is an integer number (2846189004).

Almost surely, 2^9961661507 is an apocalyptic number.

9961661507 is a deficient number, since it is larger than the sum of its proper divisors (1423094509).

9961661507 is a wasteful number, since it uses less digits than its factorization.

9961661507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1423094508.

The product of its (nonzero) digits is 612360, while the sum is 50.

The square root of 9961661507 is about 99808.1234519515. The cubic root of 9961661507 is about 2151.6779046820.

The spelling of 9961661507 in words is "nine billion, nine hundred sixty-one million, six hundred sixty-one thousand, five hundred seven".