1978651281 has 8 divisors (see below), whose sum is σ = 2642195584. Its totient is φ = 1317103920.

The previous prime is 1978651277. The next prime is 1978651313. The reversal of 1978651281 is 1821568791.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1978651281 - 2² = 1978651277 is a prime.

It is a super-2 number, since 2×1978651281² = 7830121783605881922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1978651281.

It is not an unprimeable number, because it can be changed into a prime (1978651201) 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 7 ways as a sum of consecutive naturals, for example, 496921 + ... + 500886.

It is an arithmetic number, because the mean of its divisors is an integer number (330274448).

Almost surely, 2^1978651281 is an apocalyptic number.

It is an amenable number.

1978651281 is a deficient number, since it is larger than the sum of its proper divisors (663544303).

1978651281 is an equidigital number, since it uses as much as digits as its factorization.

1978651281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 998471.

The product of its digits is 241920, while the sum is 48.

The square root of 1978651281 is about 44482.0332381513. The cubic root of 1978651281 is about 1255.4220536749.

The spelling of 1978651281 in words is "one billion, nine hundred seventy-eight million, six hundred fifty-one thousand, two hundred eighty-one".