4194557721 has 6 divisors (see below), whose sum is σ = 6058805610. Its totient is φ = 2796371808.

The previous prime is 4194557677. The next prime is 4194557737. The reversal of 4194557721 is 1277554914.

4194557721 is a `hidden beast` number, since 4 + 1 + 94 + 557 + 7 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2944581696 + 1249976025 = 54264^2 + 35355^2 .

It is not a de Polignac number, because 4194557721 - 2⁹ = 4194557209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (4194557761) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 233030976 + ... + 233030993.

It is an arithmetic number, because the mean of its divisors is an integer number (1009800935).

Almost surely, 2^4194557721 is an apocalyptic number.

It is an amenable number.

4194557721 is a deficient number, since it is larger than the sum of its proper divisors (1864247889).

4194557721 is a wasteful number, since it uses less digits than its factorization.

4194557721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 466061975 (or 466061972 counting only the distinct ones).

The product of its digits is 352800, while the sum is 45.

The square root of 4194557721 is about 64765.4052793619. The cubic root of 4194557721 is about 1612.7314615639.

The spelling of 4194557721 in words is "four billion, one hundred ninety-four million, five hundred fifty-seven thousand, seven hundred twenty-one".