49999981 has 4 divisors (see below), whose sum is σ = 50084892. Its totient is φ = 49915072.

The previous prime is 49999921. The next prime is 49999991. The reversal of 49999981 is 18999994.

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

It can be written as a sum of positive squares in 2 ways, for example, as 21206025 + 28793956 = 4605^2 + 5366^2 .

It is a cyclic number.

It is not a de Polignac number, because 49999981 - 2⁷ = 49999853 is a prime.

It is a super-2 number, since 2×49999981² = 4999996200000722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (49999921) 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, 41566 + ... + 42751.

It is an arithmetic number, because the mean of its divisors is an integer number (12521223).

Almost surely, 2^49999981 is an apocalyptic number.

It is an amenable number.

49999981 is a deficient number, since it is larger than the sum of its proper divisors (84911).

49999981 is an equidigital number, since it uses as much as digits as its factorization.

49999981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84910.

The product of its digits is 1889568, while the sum is 58.

The square root of 49999981 is about 7071.0664683625. The cubic root of 49999981 is about 368.4031031996.

The spelling of 49999981 in words is "forty-nine million, nine hundred ninety-nine thousand, nine hundred eighty-one".