9909899971 has 2 divisors, whose sum is σ = 9909899972. Its totient is φ = 9909899970.

The previous prime is 9909899953. The next prime is 9909900023. The reversal of 9909899971 is 1799989099.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9909899971 - 2²¹ = 9907802819 is a prime.

It is a super-2 number, since 2×9909899971² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 9909899971.

It is not a weakly prime, because it can be changed into another prime (9909899911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4954949985 + 4954949986.

It is an arithmetic number, because the mean of its divisors is an integer number (4954949986).

Almost surely, 2^9909899971 is an apocalyptic number.

9909899971 is a deficient number, since it is larger than the sum of its proper divisors (1).

9909899971 is an equidigital number, since it uses as much as digits as its factorization.

9909899971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 29760696, while the sum is 70.

The square root of 9909899971 is about 99548.4805057315. The cubic root of 9909899971 is about 2147.9446715315.

The spelling of 9909899971 in words is "nine billion, nine hundred nine million, eight hundred ninety-nine thousand, nine hundred seventy-one".