999972169 has 4 divisors (see below), whose sum is σ = 1142825344. Its totient is φ = 857118996.

The previous prime is 999972167. The next prime is 999972187. The reversal of 999972169 is 961279999.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 961279999 = 1427 ⋅673637.

It is a cyclic number.

It is not a de Polignac number, because 999972169 - 2¹ = 999972167 is a prime.

It is a super-2 number, since 2×999972169² = 1999888677549129122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999972167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71426577 + ... + 71426590.

It is an arithmetic number, because the mean of its divisors is an integer number (285706336).

Almost surely, 2^999972169 is an apocalyptic number.

It is an amenable number.

999972169 is a deficient number, since it is larger than the sum of its proper divisors (142853175).

999972169 is a wasteful number, since it uses less digits than its factorization.

999972169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142853174.

The product of its digits is 4960116, while the sum is 61.

The square root of 999972169 is about 31622.3365518742. The cubic root of 999972169 is about 999.9907229139.

The spelling of 999972169 in words is "nine hundred ninety-nine million, nine hundred seventy-two thousand, one hundred sixty-nine".