19810157 has 4 divisors (see below), whose sum is σ = 19904256. Its totient is φ = 19716060.

The previous prime is 19810139. The next prime is 19810159. The reversal of 19810157 is 75101891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19810157 - 2¹⁰ = 19809133 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 (19810159) 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, 46733 + ... + 47154.

It is an arithmetic number, because the mean of its divisors is an integer number (4976064).

Almost surely, 2^19810157 is an apocalyptic number.

It is an amenable number.

19810157 is a deficient number, since it is larger than the sum of its proper divisors (94099).

19810157 is an equidigital number, since it uses as much as digits as its factorization.

19810157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94098.

The product of its (nonzero) digits is 2520, while the sum is 32.

The square root of 19810157 is about 4450.8602539284. The cubic root of 19810157 is about 270.5801744708.

The spelling of 19810157 in words is "nineteen million, eight hundred ten thousand, one hundred fifty-seven".