1921157811 has 32 divisors (see below), whose sum is σ = 3172204800. Its totient is φ = 1141983360.

The previous prime is 1921157807. The next prime is 1921157857. The reversal of 1921157811 is 1187511291.

It is not a de Polignac number, because 1921157811 - 2² = 1921157807 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1921157011) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 101425 + ... + 118866.

It is an arithmetic number, because the mean of its divisors is an integer number (99131400).

Almost surely, 2^1921157811 is an apocalyptic number.

1921157811 is a deficient number, since it is larger than the sum of its proper divisors (1251046989).

1921157811 is a wasteful number, since it uses less digits than its factorization.

1921157811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220336 (or 220330 counting only the distinct ones).

The product of its digits is 5040, while the sum is 36.

The square root of 1921157811 is about 43831.0142593119. The cubic root of 1921157811 is about 1243.1427846781.

The spelling of 1921157811 in words is "one billion, nine hundred twenty-one million, one hundred fifty-seven thousand, eight hundred eleven".