1201020021 has 16 divisors (see below), whose sum is σ = 1785587520. Its totient is φ = 797845680.

The previous prime is 1201019993. The next prime is 1201020047. The reversal of 1201020021 is 1200201021.

It is not a de Polignac number, because 1201020021 - 2¹⁴ = 1201003637 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 1201019985 and 1201020012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1201020061) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70950 + ... + 86231.

It is an arithmetic number, because the mean of its divisors is an integer number (111599220).

Almost surely, 2^1201020021 is an apocalyptic number.

It is an amenable number.

1201020021 is a deficient number, since it is larger than the sum of its proper divisors (584567499).

1201020021 is a wasteful number, since it uses less digits than its factorization.

1201020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157473 (or 157467 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1201020021 is about 34655.7357590342. The cubic root of 1201020021 is about 1062.9595767049.

Adding to 1201020021 its reverse (1200201021), we get a palindrome (2401221042).

The spelling of 1201020021 in words is "one billion, two hundred one million, twenty thousand, twenty-one".