1671000721 has 16 divisors (see below), whose sum is σ = 1836006480. Its totient is φ = 1511516160.

The previous prime is 1671000701. The next prime is 1671000743. The reversal of 1671000721 is 1270001761.

It can be written as a sum of positive squares in 8 ways, for example, as 476330625 + 1194670096 = 21825^2 + 34564^2 .

It is a cyclic number.

It is not a de Polignac number, because 1671000721 - 2¹⁹ = 1670476433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1671000701) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 124351 + ... + 137131.

It is an arithmetic number, because the mean of its divisors is an integer number (114750405).

Almost surely, 2^1671000721 is an apocalyptic number.

It is an amenable number.

1671000721 is a deficient number, since it is larger than the sum of its proper divisors (165005759).

1671000721 is a wasteful number, since it uses less digits than its factorization.

1671000721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12996.

The product of its (nonzero) digits is 588, while the sum is 25.

The square root of 1671000721 is about 40877.8756908918. The cubic root of 1671000721 is about 1186.6579298670.

The spelling of 1671000721 in words is "one billion, six hundred seventy-one million, seven hundred twenty-one", and thus it is an aban number.