999995551 has 4 divisors (see below), whose sum is σ = 1032253504. Its totient is φ = 967737600.

The previous prime is 999995531. The next prime is 999995561. The reversal of 999995551 is 155599999.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999995551 is a prime.

It is a super-2 number, since 2×999995551² = 1999982204039587202, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 999995551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999995531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16128930 + ... + 16128991.

It is an arithmetic number, because the mean of its divisors is an integer number (258063376).

Almost surely, 2^999995551 is an apocalyptic number.

999995551 is a deficient number, since it is larger than the sum of its proper divisors (32257953).

999995551 is a wasteful number, since it uses less digits than its factorization.

999995551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32257952.

The product of its digits is 7381125, while the sum is 61.

The square root of 999995551 is about 31622.7062567390. The cubic root of 999995551 is about 999.9985169978.

The spelling of 999995551 in words is "nine hundred ninety-nine million, nine hundred ninety-five thousand, five hundred fifty-one".