1920137861 has 4 divisors (see below), whose sum is σ = 1982077824. Its totient is φ = 1858197900.

The previous prime is 1920137851. The next prime is 1920137873. The reversal of 1920137861 is 1687310291.

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.

It is a cyclic number.

It is not a de Polignac number, because 1920137861 - 2⁶ = 1920137797 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1920137801) 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, 30969935 + ... + 30969996.

It is an arithmetic number, because the mean of its divisors is an integer number (495519456).

Almost surely, 2^1920137861 is an apocalyptic number.

It is an amenable number.

1920137861 is a deficient number, since it is larger than the sum of its proper divisors (61939963).

1920137861 is an equidigital number, since it uses as much as digits as its factorization.

1920137861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61939962.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 1920137861 is about 43819.3776884154. The cubic root of 1920137861 is about 1242.9227493210.

The spelling of 1920137861 in words is "one billion, nine hundred twenty million, one hundred thirty-seven thousand, eight hundred sixty-one".