1201661021 has 16 divisors (see below), whose sum is σ = 1349318400. Its totient is φ = 1060862400.

The previous prime is 1201660981. The next prime is 1201661033.

1201661021 is nontrivially palindromic in base 10.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1201661021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1201660984 and 1201661002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1201661521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41675 + ... + 64343.

It is an arithmetic number, because the mean of its divisors is an integer number (84332400).

Almost surely, 2^1201661021 is an apocalyptic number.

1201661021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1201661021 is a deficient number, since it is larger than the sum of its proper divisors (147657379).

1201661021 is a wasteful number, since it uses less digits than its factorization.

1201661021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22820.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 1201661021 is about 34664.9826337761. The cubic root of 1201661021 is about 1063.1486481876.

It can be divided in two parts, 12016 and 61021, that added together give a palindrome (73037).

The spelling of 1201661021 in words is "one billion, two hundred one million, six hundred sixty-one thousand, twenty-one".