1931338809 has 45 divisors (see below), whose sum is σ = 3056819007. Its totient is φ = 1215046656.

The previous prime is 1931338807. The next prime is 1931338823. The reversal of 1931338809 is 9088331391.

It is a happy number.

The square root of 1931338809 is 43947.

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., 1901396025 + 29942784 = 43605^2 + 5472^2 .

It is not a de Polignac number, because 1931338809 - 2¹ = 1931338807 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1931338807) 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 44 ways as a sum of consecutive naturals, for example, 7514809 + ... + 7515065.

Almost surely, 2^1931338809 is an apocalyptic number.

1931338809 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1931338809 is the 43947-th square number.

1931338809 is the 21974-th centered octagonal number.

It is an amenable number.

1931338809 is a deficient number, since it is larger than the sum of its proper divisors (1125480198).

1931338809 is an frugal number, since it uses more digits than its factorization.

1931338809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 564 (or 279 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The cubic root of 1931338809 is about 1245.3348903139.

The spelling of 1931338809 in words is "one billion, nine hundred thirty-one million, three hundred thirty-eight thousand, eight hundred nine".