1200012021 has 24 divisors (see below), whose sum is σ = 1869512736. Its totient is φ = 737350560.

The previous prime is 1200012019. The next prime is 1200012053. The reversal of 1200012021 is 1202100021.

It is not a de Polignac number, because 1200012021 - 2¹ = 1200012019 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 = 1200011994 and 1200012012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1200012001) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 73426 + ... + 88268.

It is an arithmetic number, because the mean of its divisors is an integer number (77896364).

Almost surely, 2^1200012021 is an apocalyptic number.

It is an amenable number.

1200012021 is a deficient number, since it is larger than the sum of its proper divisors (669500715).

1200012021 is a wasteful number, since it uses less digits than its factorization.

1200012021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15553 (or 15550 counting only the distinct ones).

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

The square root of 1200012021 is about 34641.1896591327. The cubic root of 1200012021 is about 1062.6621175648.

Adding to 1200012021 its reverse (1202100021), we get a palindrome (2402112042).

The spelling of 1200012021 in words is "one billion, two hundred million, twelve thousand, twenty-one".