19691057 has 4 divisors (see below), whose sum is σ = 19719540. Its totient is φ = 19662576.

The previous prime is 19691053. The next prime is 19691129. The reversal of 19691057 is 75019691.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7187761 + 12503296 = 2681^2 + 3536^2 .

It is a cyclic number.

It is not a de Polignac number, because 19691057 - 2² = 19691053 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 19691057.

It is not an unprimeable number, because it can be changed into a prime (19691051) 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, 13178 + ... + 14595.

It is an arithmetic number, because the mean of its divisors is an integer number (4929885).

Almost surely, 2^19691057 is an apocalyptic number.

It is an amenable number.

19691057 is a deficient number, since it is larger than the sum of its proper divisors (28483).

19691057 is an equidigital number, since it uses as much as digits as its factorization.

19691057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28482.

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

The square root of 19691057 is about 4437.4606477128. The cubic root of 19691057 is about 270.0368353951.

The spelling of 19691057 in words is "nineteen million, six hundred ninety-one thousand, fifty-seven".