65778973638 has 16 divisors (see below), whose sum is σ = 150351939840.
Its totient is φ = 18793992456.
The previous prime is 65778973633. The next prime is 65778973649. The reversal of 65778973638 is 83637987756.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (65778973633) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 783082978 + ... + 783083061.
It is an arithmetic number, because the mean of its divisors is an integer number (9396996240).
Almost surely, 265778973638 is an apocalyptic number.
65778973638 is an abundant number, since it is smaller than the sum of its proper divisors (84572966202).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
65778973638 is a wasteful number, since it uses less digits than its factorization.
65778973638 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 1566166051.
The product of its digits is 320060160, while the sum is 69.
The spelling of 65778973638 in words is "sixty-five billion, seven hundred seventy-eight million, nine hundred seventy-three thousand, six hundred thirty-eight".