1205142021 has 12 divisors (see below), whose sum is σ = 1745753100. Its totient is φ = 801123840.

The previous prime is 1205141953. The next prime is 1205142031. The reversal of 1205142021 is 1202415021.

It can be written as a sum of positive squares in 2 ways, for example, as 1042579521 + 162562500 = 32289^2 + 12750^2 .

It is not a de Polignac number, because 1205142021 - 2¹⁰ = 1205140997 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1205141985 and 1205142003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205142031) 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, 188700 + ... + 194981.

It is an arithmetic number, because the mean of its divisors is an integer number (145479425).

Almost surely, 2^1205142021 is an apocalyptic number.

It is an amenable number.

1205142021 is a deficient number, since it is larger than the sum of its proper divisors (540611079).

1205142021 is a wasteful number, since it uses less digits than its factorization.

1205142021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384036 (or 384033 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 1205142021 is about 34715.1554943947. The cubic root of 1205142021 is about 1064.1742431983.

Adding to 1205142021 its reverse (1202415021), we get a palindrome (2407557042).

The spelling of 1205142021 in words is "one billion, two hundred five million, one hundred forty-two thousand, twenty-one".