99999901 has 4 divisors (see below), whose sum is σ = 100662304. Its totient is φ = 99337500.

The previous prime is 99999847. The next prime is 99999931. The reversal of 99999901 is 10999999.

It is a happy number.

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: 10999999 = 509 ⋅21611.

It is a cyclic number.

It is not a de Polignac number, because 99999901 - 2⁷ = 99999773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99999931) 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, 330975 + ... + 331276.

It is an arithmetic number, because the mean of its divisors is an integer number (25165576).

Almost surely, 2^99999901 is an apocalyptic number.

It is an amenable number.

99999901 is a deficient number, since it is larger than the sum of its proper divisors (662403).

99999901 is a wasteful number, since it uses less digits than its factorization.

99999901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662402.

The product of its (nonzero) digits is 531441, while the sum is 55.

The square root of 99999901 is about 9999.9950499988. The cubic root of 99999901 is about 464.1587301888.

Subtracting from 99999901 its product of nonzero digits (531441), we obtain a triangular number (99468460 = T₁₄₁₀₄).

It can be divided in two parts, 9999 and 9901, that multiplied together give a palindrome (99000099).

The spelling of 99999901 in words is "ninety-nine million, nine hundred ninety-nine thousand, nine hundred one".