18961791 has 16 divisors (see below), whose sum is σ = 26870400. Its totient is φ = 11860128.

The previous prime is 18961771. The next prime is 18961793. The reversal of 18961791 is 19716981.

It is not a de Polignac number, because 18961791 - 2¹⁸ = 18699647 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18961793) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4545 + ... + 7653.

It is an arithmetic number, because the mean of its divisors is an integer number (1679400).

Almost surely, 2^18961791 is an apocalyptic number.

18961791 is a deficient number, since it is larger than the sum of its proper divisors (7908609).

18961791 is a wasteful number, since it uses less digits than its factorization.

18961791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3238.

The product of its digits is 27216, while the sum is 42.

The square root of 18961791 is about 4354.5138649452. The cubic root of 18961791 is about 266.6611729771.

The spelling of 18961791 in words is "eighteen million, nine hundred sixty-one thousand, seven hundred ninety-one".