201021993 has 12 divisors (see below), whose sum is σ = 301119728. Its totient is φ = 134014500.

The previous prime is 201021973. The next prime is 201022007. The reversal of 201021993 is 399120102.

It is a de Polignac number, because none of the positive numbers 2^k-201021993 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (201021913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 413383 + ... + 413868.

Almost surely, 2^201021993 is an apocalyptic number.

It is an amenable number.

201021993 is a deficient number, since it is larger than the sum of its proper divisors (100097735).

201021993 is an frugal number, since it uses more digits than its factorization.

201021993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 827266 (or 827254 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 201021993 is about 14178.2224908484. Note that the first 3 decimals coincide. The cubic root of 201021993 is about 585.7979643031.

The spelling of 201021993 in words is "two hundred one million, twenty-one thousand, nine hundred ninety-three".