201621638 has 8 divisors (see below), whose sum is σ = 303065280. Its totient is φ = 100599880.

The previous prime is 201621619. The next prime is 201621643. The reversal of 201621638 is 836126102.

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 201621638.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104273 + ... + 106188.

It is an arithmetic number, because the mean of its divisors is an integer number (37883160).

Almost surely, 2^201621638 is an apocalyptic number.

201621638 is a deficient number, since it is larger than the sum of its proper divisors (101443642).

201621638 is a wasteful number, since it uses less digits than its factorization.

201621638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210942.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 201621638 is about 14199.3534359843. The cubic root of 201621638 is about 586.3798610308.

The spelling of 201621638 in words is "two hundred one million, six hundred twenty-one thousand, six hundred thirty-eight".