1921166801 has 4 divisors (see below), whose sum is σ = 1928821104. Its totient is φ = 1913512500.

The previous prime is 1921166789. The next prime is 1921166803. The reversal of 1921166801 is 1086611291.

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: 1086611291 = 373 ⋅2913167.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1921166801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1921166803) 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, 3826775 + ... + 3827276.

It is an arithmetic number, because the mean of its divisors is an integer number (482205276).

Almost surely, 2^1921166801 is an apocalyptic number.

It is an amenable number.

1921166801 is a deficient number, since it is larger than the sum of its proper divisors (7654303).

1921166801 is an equidigital number, since it uses as much as digits as its factorization.

1921166801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7654302.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 1921166801 is about 43831.1168121461. The cubic root of 1921166801 is about 1243.1447237581.

The spelling of 1921166801 in words is "one billion, nine hundred twenty-one million, one hundred sixty-six thousand, eight hundred one".