1201981905 has 12 divisors (see below), whose sum is σ = 2083435380. Its totient is φ = 641056992.

The previous prime is 1201981903. The next prime is 1201981931. The reversal of 1201981905 is 5091891021.

It can be written as a sum of positive squares in 2 ways, for example, as 223293249 + 978688656 = 14943^2 + 31284^2 .

It is not a de Polignac number, because 1201981905 - 2¹ = 1201981903 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1201981905.

It is not an unprimeable number, because it can be changed into a prime (1201981903) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13355310 + ... + 13355399.

It is an arithmetic number, because the mean of its divisors is an integer number (173619615).

Almost surely, 2^1201981905 is an apocalyptic number.

1201981905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1201981905 is a deficient number, since it is larger than the sum of its proper divisors (881453475).

1201981905 is a wasteful number, since it uses less digits than its factorization.

1201981905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26710720 (or 26710717 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 36.

The square root of 1201981905 is about 34669.6106842866. The cubic root of 1201981905 is about 1063.2432719413.

The spelling of 1201981905 in words is "one billion, two hundred one million, nine hundred eighty-one thousand, nine hundred five".