49999903665721 has 3 divisors (see below), whose sum is σ = 49999910736783. Its totient is φ = 49999896594660.

The previous prime is 49999903665683. The next prime is 49999903665737. The reversal of 49999903665721 is 12756630999994.

The square root of 49999903665721 is 7071061.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 40788800065321 + 9211103600400 = 6386611^2 + 3034980^2 .

It is not a de Polignac number, because 49999903665721 - 2⁹ = 49999903665209 is a prime.

It is a super-3 number, since 3×49999903665721³ (a number of 42 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (49999903662721) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 3535531 + ... + 10606591.

It is an arithmetic number, because the mean of its divisors is an integer number (16666636912261).

Almost surely, 2^{49999903665721} is an apocalyptic number.

49999903665721 is the 7071061-st square number.

49999903665721 is the 3535531-st centered octagonal number.

It is an amenable number.

49999903665721 is a deficient number, since it is larger than the sum of its proper divisors (7071062).

49999903665721 is an frugal number, since it uses more digits than its factorization.

49999903665721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14142122 (or 7071061 counting only the distinct ones).

The product of its (nonzero) digits is 1785641760, while the sum is 79.

The spelling of 49999903665721 in words is "forty-nine trillion, nine hundred ninety-nine billion, nine hundred three million, six hundred sixty-five thousand, seven hundred twenty-one".