99971819 has 4 divisors (see below), whose sum is σ = 99997944. Its totient is φ = 99945696.

The previous prime is 99971813. The next prime is 99971827. The reversal of 99971819 is 91817999.

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 99971819 - 2⁴ = 99971803 is a prime.

It is a super-2 number, since 2×99971819² = 19988729188337522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99971813) 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, 6077 + ... + 15390.

It is an arithmetic number, because the mean of its divisors is an integer number (24999486).

Almost surely, 2^99971819 is an apocalyptic number.

99971819 is a deficient number, since it is larger than the sum of its proper divisors (26125).

99971819 is a wasteful number, since it uses less digits than its factorization.

99971819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26124.

The product of its digits is 367416, while the sum is 53.

The square root of 99971819 is about 9998.5908507149. The cubic root of 99971819 is about 464.1152777265.

The spelling of 99971819 in words is "ninety-nine million, nine hundred seventy-one thousand, eight hundred nineteen".