20199621 has 16 divisors (see below), whose sum is σ = 30711744. Its totient is φ = 11698944.

The previous prime is 20199617. The next prime is 20199623. The reversal of 20199621 is 12699102.

It is a happy number.

It is not a de Polignac number, because 20199621 - 2² = 20199617 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20199623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14571 + ... + 15896.

It is an arithmetic number, because the mean of its divisors is an integer number (1919484).

Almost surely, 2^20199621 is an apocalyptic number.

It is an amenable number.

20199621 is a deficient number, since it is larger than the sum of its proper divisors (10512123).

20199621 is a wasteful number, since it uses less digits than its factorization.

20199621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30500.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 20199621 is about 4494.3988474545. The cubic root of 20199621 is about 272.3418648754.

The spelling of 20199621 in words is "twenty million, one hundred ninety-nine thousand, six hundred twenty-one".