49801991 has 4 divisors (see below), whose sum is σ = 50259000. Its totient is φ = 49344984.

The previous prime is 49801981. The next prime is 49802009. The reversal of 49801991 is 19910894.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19910894 = 2 ⋅9955447.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-49801991 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 (49801981) 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, 228341 + ... + 228558.

It is an arithmetic number, because the mean of its divisors is an integer number (12564750).

Almost surely, 2^49801991 is an apocalyptic number.

49801991 is a deficient number, since it is larger than the sum of its proper divisors (457009).

49801991 is a wasteful number, since it uses less digits than its factorization.

49801991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 457008.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 49801991 is about 7057.0525717186. The cubic root of 49801991 is about 367.9161922219.

The spelling of 49801991 in words is "forty-nine million, eight hundred one thousand, nine hundred ninety-one".