16210991 has 4 divisors (see below), whose sum is σ = 16237800. Its totient is φ = 16184184.

The previous prime is 16210981. The next prime is 16210993. The reversal of 16210991 is 19901261.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 16210991 - 2⁶ = 16210927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16210993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12476 + ... + 13713.

It is an arithmetic number, because the mean of its divisors is an integer number (4059450).

Almost surely, 2^16210991 is an apocalyptic number.

16210991 is a deficient number, since it is larger than the sum of its proper divisors (26809).

16210991 is an equidigital number, since it uses as much as digits as its factorization.

16210991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26808.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 16210991 is about 4026.2874959446. The cubic root of 16210991 is about 253.0870099161.

The spelling of 16210991 in words is "sixteen million, two hundred ten thousand, nine hundred ninety-one".