1945148781 has 4 divisors (see below), whose sum is σ = 2593531712. Its totient is φ = 1296765852.

The previous prime is 1945148771. The next prime is 1945148791. The reversal of 1945148781 is 1878415491.

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 an interprime number because it is at equal distance from previous prime (1945148771) and next prime (1945148791).

It is not a de Polignac number, because 1945148781 - 2⁵ = 1945148749 is a prime.

It is a super-2 number, since 2×1945148781² = 7567207560451571922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1945148781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1945148701) 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 3 ways as a sum of consecutive naturals, for example, 324191461 + ... + 324191466.

It is an arithmetic number, because the mean of its divisors is an integer number (648382928).

Almost surely, 2^1945148781 is an apocalyptic number.

It is an amenable number.

1945148781 is a deficient number, since it is larger than the sum of its proper divisors (648382931).

1945148781 is an equidigital number, since it uses as much as digits as its factorization.

1945148781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 648382930.

The product of its digits is 322560, while the sum is 48.

The square root of 1945148781 is about 44103.8408871608. The cubic root of 1945148781 is about 1248.2960850077.

The spelling of 1945148781 in words is "one billion, nine hundred forty-five million, one hundred forty-eight thousand, seven hundred eighty-one".