1978462639 has 4 divisors (see below), whose sum is σ = 1998051480. Its totient is φ = 1958873800.

The previous prime is 1978462627. The next prime is 1978462643. The reversal of 1978462639 is 9362648791.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1978462639 - 2⁷ = 1978462511 is a prime.

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 1978462639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978462939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9794269 + ... + 9794470.

It is an arithmetic number, because the mean of its divisors is an integer number (499512870).

Almost surely, 2^1978462639 is an apocalyptic number.

1978462639 is a deficient number, since it is larger than the sum of its proper divisors (19588841).

1978462639 is a wasteful number, since it uses less digits than its factorization.

1978462639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19588840.

The product of its digits is 3919104, while the sum is 55.

The square root of 1978462639 is about 44479.9127584576. The cubic root of 1978462639 is about 1255.3821556467.

The spelling of 1978462639 in words is "one billion, nine hundred seventy-eight million, four hundred sixty-two thousand, six hundred thirty-nine".