1900000921 has 27 divisors (see below), whose sum is σ = 2398305951. Its totient is φ = 1500159024.

The previous prime is 1900000919. The next prime is 1900000979. The reversal of 1900000921 is 1290000091.

The square root of 1900000921 is 43589.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 281065225 + 1618935696 = 16765^2 + 40236^2 .

It is not a de Polignac number, because 1900000921 - 2¹ = 1900000919 is a prime.

It is a super-2 number, since 2×1900000921² = 7220006999601696482, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1900000892 and 1900000901.

It is not an unprimeable number, because it can be changed into a prime (1900000901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 3966360 + ... + 3966838.

Almost surely, 2^1900000921 is an apocalyptic number.

1900000921 is the 43589-th square number.

1900000921 is the 21795-th centered octagonal number.

It is an amenable number.

1900000921 is a deficient number, since it is larger than the sum of its proper divisors (498305030).

1900000921 is an frugal number, since it uses more digits than its factorization.

1900000921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 998 (or 499 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 22.

The cubic root of 1900000921 is about 1238.5625297557.

The spelling of 1900000921 in words is "one billion, nine hundred million, nine hundred twenty-one", and thus it is an aban number.