1691381273 has 4 divisors (see below), whose sum is σ = 1780401360. Its totient is φ = 1602361188.

The previous prime is 1691381257. The next prime is 1691381287. The reversal of 1691381273 is 3721831961.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1691381273 - 2⁴ = 1691381257 is a prime.

It is a super-2 number, since 2×1691381273² = 5721541221310201058, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1691381273.

It is not an unprimeable number, because it can be changed into a prime (1691381243) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44510015 + ... + 44510052.

It is an arithmetic number, because the mean of its divisors is an integer number (445100340).

Almost surely, 2^1691381273 is an apocalyptic number.

It is an amenable number.

1691381273 is a deficient number, since it is larger than the sum of its proper divisors (89020087).

1691381273 is an equidigital number, since it uses as much as digits as its factorization.

1691381273 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89020086.

The product of its digits is 54432, while the sum is 41.

The square root of 1691381273 is about 41126.4060306757. The cubic root of 1691381273 is about 1191.4628510952.

The spelling of 1691381273 in words is "one billion, six hundred ninety-one million, three hundred eighty-one thousand, two hundred seventy-three".