1231305 has 32 divisors (see below), whose sum is σ = 2128896. Its totient is φ = 606144.

The previous prime is 1231303. The next prime is 1231309. The reversal of 1231305 is 5031321.

It is a happy number.

It is not a de Polignac number, because 1231305 - 2¹ = 1231303 is a prime.

It is a super-2 number, since 2×1231305² = 3032224006050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (1231301) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14794 + ... + 14876.

It is an arithmetic number, because the mean of its divisors is an integer number (66528).

2^1231305 is an apocalyptic number.

1231305 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1231305 is a deficient number, since it is larger than the sum of its proper divisors (897591).

1231305 is a wasteful number, since it uses less digits than its factorization.

1231305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 1231305 is about 1109.6418341068. The cubic root of 1231305 is about 107.1820060111.

Adding to 1231305 its reverse (5031321), we get a palindrome (6262626).

The spelling of 1231305 in words is "one million, two hundred thirty-one thousand, three hundred five".