1205499981 has 8 divisors (see below), whose sum is σ = 1836952384. Its totient is φ = 688857120.

The previous prime is 1205499961. The next prime is 1205499991. The reversal of 1205499981 is 1899945021.

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

It is not a de Polignac number, because 1205499981 - 2¹⁸ = 1205237837 is a prime.

It is a super-2 number, since 2×1205499981² = 2906460408382000722, which contains 22 as substring.

It is a Duffinian number.

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 1205499981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205499961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28702360 + ... + 28702401.

It is an arithmetic number, because the mean of its divisors is an integer number (229619048).

Almost surely, 2^1205499981 is an apocalyptic number.

It is an amenable number.

1205499981 is a deficient number, since it is larger than the sum of its proper divisors (631452403).

1205499981 is an equidigital number, since it uses as much as digits as its factorization.

1205499981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57404771.

The product of its (nonzero) digits is 233280, while the sum is 48.

The square root of 1205499981 is about 34720.3107848994. The cubic root of 1205499981 is about 1064.2795956784.

The spelling of 1205499981 in words is "one billion, two hundred five million, four hundred ninety-nine thousand, nine hundred eighty-one".