16071991 has 4 divisors (see below), whose sum is σ = 17308312. Its totient is φ = 14835672.

The previous prime is 16071989. The next prime is 16072019. The reversal of 16071991 is 19917061.

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 16071991 - 2¹ = 16071989 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 (16071901) 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, 618141 + ... + 618166.

It is an arithmetic number, because the mean of its divisors is an integer number (4327078).

Almost surely, 2^16071991 is an apocalyptic number.

16071991 is a deficient number, since it is larger than the sum of its proper divisors (1236321).

16071991 is a wasteful number, since it uses less digits than its factorization.

16071991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1236320.

The product of its (nonzero) digits is 3402, while the sum is 34.

The square root of 16071991 is about 4008.9887752400. The cubic root of 16071991 is about 252.3615736368.

The spelling of 16071991 in words is "sixteen million, seventy-one thousand, nine hundred ninety-one".