1321745731 has 8 divisors (see below), whose sum is σ = 1369166400. Its totient is φ = 1274448000.

The previous prime is 1321745717. The next prime is 1321745771. The reversal of 1321745731 is 1375471231.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1321745731 - 2¹⁷ = 1321614659 is a prime.

It is a super-2 number, since 2×1321745731² = 3494023554833448722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1321745771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8566 + ... + 52123.

It is an arithmetic number, because the mean of its divisors is an integer number (171145800).

Almost surely, 2^1321745731 is an apocalyptic number.

1321745731 is a deficient number, since it is larger than the sum of its proper divisors (47420669).

1321745731 is an equidigital number, since it uses as much as digits as its factorization.

1321745731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61469.

The product of its digits is 17640, while the sum is 34.

The square root of 1321745731 is about 36355.8211432502. The cubic root of 1321745731 is about 1097.4446831569. Note that the first 3 decimals are identical.

The spelling of 1321745731 in words is "one billion, three hundred twenty-one million, seven hundred forty-five thousand, seven hundred thirty-one".