37891993 has 2 divisors, whose sum is σ = 37891994. Its totient is φ = 37891992.

The previous prime is 37891981. The next prime is 37891999. The reversal of 37891993 is 39919873.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25522704 + 12369289 = 5052^2 + 3517^2 .

It is a cyclic number.

It is not a de Polignac number, because 37891993 - 2²⁵ = 4337561 is a prime.

It is not a weakly prime, because it can be changed into another prime (37891999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18945996 + 18945997.

It is an arithmetic number, because the mean of its divisors is an integer number (18945997).

Almost surely, 2^37891993 is an apocalyptic number.

It is an amenable number.

37891993 is a deficient number, since it is larger than the sum of its proper divisors (1).

37891993 is an equidigital number, since it uses as much as digits as its factorization.

37891993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 367416, while the sum is 49.

The square root of 37891993 is about 6155.6472446039. The cubic root of 37891993 is about 335.8787148467.

The spelling of 37891993 in words is "thirty-seven million, eight hundred ninety-one thousand, nine hundred ninety-three".