16953991 has 4 divisors (see below), whose sum is σ = 16983952. Its totient is φ = 16924032.

The previous prime is 16953983. The next prime is 16954001. The reversal of 16953991 is 19935961.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19935961 = 43 ⋅463627.

It is a cyclic number.

It is not a de Polignac number, because 16953991 - 2³ = 16953983 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 (16953971) 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, 14115 + ... + 15268.

It is an arithmetic number, because the mean of its divisors is an integer number (4245988).

Almost surely, 2^16953991 is an apocalyptic number.

16953991 is a deficient number, since it is larger than the sum of its proper divisors (29961).

16953991 is an equidigital number, since it uses as much as digits as its factorization.

16953991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29960.

The product of its digits is 65610, while the sum is 43.

The square root of 16953991 is about 4117.5224346687. The cubic root of 16953991 is about 256.8959845949.

The spelling of 16953991 in words is "sixteen million, nine hundred fifty-three thousand, nine hundred ninety-one".