1206138921 has 8 divisors (see below), whose sum is σ = 1731891840. Its totient is φ = 742239312.

The previous prime is 1206138919. The next prime is 1206138937. The reversal of 1206138921 is 1298316021.

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

It is not a de Polignac number, because 1206138921 - 2¹ = 1206138919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1206138991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15463281 + ... + 15463358.

It is an arithmetic number, because the mean of its divisors is an integer number (216486480).

Almost surely, 2^1206138921 is an apocalyptic number.

It is an amenable number.

1206138921 is a deficient number, since it is larger than the sum of its proper divisors (525752919).

1206138921 is a wasteful number, since it uses less digits than its factorization.

1206138921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30926655.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 1206138921 is about 34729.5108085328. The cubic root of 1206138921 is about 1064.4675925569.

The spelling of 1206138921 in words is "one billion, two hundred six million, one hundred thirty-eight thousand, nine hundred twenty-one".