1673709921 has 27 divisors (see below), whose sum is σ = 2620351929. Its totient is φ = 1028993472.

The previous prime is 1673709907. The next prime is 1673709929. The reversal of 1673709921 is 1299073761.

The square root of 1673709921 is 40911.

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

It can be written as a sum of positive squares in 4 ways, for example, as 12006225 + 1661703696 = 3465^2 + 40764^2 .

It is not a de Polignac number, because 1673709921 - 2¹⁵ = 1673677153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1673709929) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1595005 + ... + 1596053.

Almost surely, 2^1673709921 is an apocalyptic number.

1673709921 is the 40911-st square number.

1673709921 is the 20456-th centered octagonal number.

It is an amenable number.

1673709921 is a deficient number, since it is larger than the sum of its proper divisors (946642008).

1673709921 is an equidigital number, since it uses as much as digits as its factorization.

1673709921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2130 (or 1065 counting only the distinct ones).

The product of its (nonzero) digits is 142884, while the sum is 45.

The cubic root of 1673709921 is about 1187.2988946387.

Multiplying 1673709921 by its product of nonzero digits (142884), we get a square (239146368352164 = 15464358²).

The spelling of 1673709921 in words is "one billion, six hundred seventy-three million, seven hundred nine thousand, nine hundred twenty-one".