1921519157 has 4 divisors (see below), whose sum is σ = 1922303040. Its totient is φ = 1920735276.

The previous prime is 1921519151. The next prime is 1921519183. The reversal of 1921519157 is 7519151291.

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: 7519151291 = 29 ⋅259281079.

It is a cyclic number.

It is not a de Polignac number, because 1921519157 - 2⁸ = 1921518901 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 (1921519151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 388253 + ... + 393170.

It is an arithmetic number, because the mean of its divisors is an integer number (480575760).

Almost surely, 2^1921519157 is an apocalyptic number.

It is an amenable number.

1921519157 is a deficient number, since it is larger than the sum of its proper divisors (783883).

1921519157 is an equidigital number, since it uses as much as digits as its factorization.

1921519157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783882.

The product of its digits is 28350, while the sum is 41.

The square root of 1921519157 is about 43835.1361010776. The cubic root of 1921519157 is about 1243.2207197146.

The spelling of 1921519157 in words is "one billion, nine hundred twenty-one million, five hundred nineteen thousand, one hundred fifty-seven".