19906157 has 4 divisors (see below), whose sum is σ = 19938336. Its totient is φ = 19873980.

The previous prime is 19906153. The next prime is 19906171. The reversal of 19906157 is 75160991.

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, and also an emirpimes, since its reverse is a distinct semiprime: 75160991 = 2239 ⋅33569.

It is a cyclic number.

It is not a de Polignac number, because 19906157 - 2² = 19906153 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19906157.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19906153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15143 + ... + 16404.

It is an arithmetic number, because the mean of its divisors is an integer number (4984584).

Almost surely, 2^19906157 is an apocalyptic number.

It is an amenable number.

19906157 is a deficient number, since it is larger than the sum of its proper divisors (32179).

19906157 is an equidigital number, since it uses as much as digits as its factorization.

19906157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32178.

The product of its (nonzero) digits is 17010, while the sum is 38.

The square root of 19906157 is about 4461.6316522098. The cubic root of 19906157 is about 271.0165474208.

The spelling of 19906157 in words is "nineteen million, nine hundred six thousand, one hundred fifty-seven".