16199921 has 2 divisors, whose sum is σ = 16199922. Its totient is φ = 16199920.

The previous prime is 16199917. The next prime is 16199971. The reversal of 16199921 is 12999161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10817521 + 5382400 = 3289^2 + 2320^2 .

It is a cyclic number.

It is not a de Polignac number, because 16199921 - 2² = 16199917 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16199971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8099960 + 8099961.

It is an arithmetic number, because the mean of its divisors is an integer number (8099961).

Almost surely, 2^16199921 is an apocalyptic number.

It is an amenable number.

16199921 is a deficient number, since it is larger than the sum of its proper divisors (1).

16199921 is an equidigital number, since it uses as much as digits as its factorization.

16199921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8748, while the sum is 38.

The square root of 16199921 is about 4024.9125456338. The cubic root of 16199921 is about 253.0293882863.

The spelling of 16199921 in words is "sixteen million, one hundred ninety-nine thousand, nine hundred twenty-one".