999855001 has 2 divisors, whose sum is σ = 999855002. Its totient is φ = 999855000.

The previous prime is 999854981. The next prime is 999855007. The reversal of 999855001 is 100558999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 991305225 + 8549776 = 31485^2 + 2924^2 .

It is an emirp because it is prime and its reverse (100558999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999855001 - 2⁵ = 999854969 is a prime.

It is not a weakly prime, because it can be changed into another prime (999855007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499927500 + 499927501.

It is an arithmetic number, because the mean of its divisors is an integer number (499927501).

Almost surely, 2^999855001 is an apocalyptic number.

It is an amenable number.

999855001 is a deficient number, since it is larger than the sum of its proper divisors (1).

999855001 is an equidigital number, since it uses as much as digits as its factorization.

999855001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145800, while the sum is 46.

The square root of 999855001 is about 31620.4838830781. The cubic root of 999855001 is about 999.9516646637.

The spelling of 999855001 in words is "nine hundred ninety-nine million, eight hundred fifty-five thousand, one".