1205321390 has 64 divisors (see below), whose sum is σ = 2732438016. Its totient is φ = 372580992.

The previous prime is 1205321339. The next prime is 1205321399. The reversal of 1205321390 is 931235021.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205321399) 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, 23729 + ... + 54531.

It is an arithmetic number, because the mean of its divisors is an integer number (42694344).

Almost surely, 2^1205321390 is an apocalyptic number.

1205321390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1205321390 is an abundant number, since it is smaller than the sum of its proper divisors (1527116626).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1205321390 is a wasteful number, since it uses less digits than its factorization.

1205321390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30873.

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 1205321390 is about 34717.7388376605. The cubic root of 1205321390 is about 1064.2270365336.

The spelling of 1205321390 in words is "one billion, two hundred five million, three hundred twenty-one thousand, three hundred ninety".