834147721 has 32 divisors (see below), whose sum is σ = 1021731840. Its totient is φ = 671846400.

The previous prime is 834147701. The next prime is 834147767. The reversal of 834147721 is 127741438.

It is a 4-Lehmer number, since φ(834147721) divides (834147721-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 834147721 - 2¹¹ = 834145673 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (834147701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 212545 + ... + 216433.

It is an arithmetic number, because the mean of its divisors is an integer number (31929120).

It is a Poulet number, since it divides 2^834147720-1.

Almost surely, 2^834147721 is an apocalyptic number.

It is an amenable number.

834147721 is a deficient number, since it is larger than the sum of its proper divisors (187584119).

834147721 is a wasteful number, since it uses less digits than its factorization.

834147721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3985.

The product of its digits is 37632, while the sum is 37.

The square root of 834147721 is about 28881.6156230914. The cubic root of 834147721 is about 941.3424763302.

The spelling of 834147721 in words is "eight hundred thirty-four million, one hundred forty-seven thousand, seven hundred twenty-one".