635978209642 has 8 divisors (see below), whose sum is σ = 953975469636. Its totient is φ = 317986386432.

The previous prime is 635978209613. The next prime is 635978209649. The reversal of 635978209642 is 246902879536.

It can be written as a sum of positive squares in 2 ways, for example, as 635928097401 + 50112241 = 797451^2 + 7079^2 .

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

It is not an unprimeable number, because it can be changed into a prime (635978209649) 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, 1052953 + ... + 1542940.

Almost surely, 2^635978209642 is an apocalyptic number.

635978209642 is a deficient number, since it is larger than the sum of its proper divisors (317997259994).

635978209642 is a wasteful number, since it uses less digits than its factorization.

635978209642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2718392.

The product of its (nonzero) digits is 39191040, while the sum is 61.

The spelling of 635978209642 in words is "six hundred thirty-five billion, nine hundred seventy-eight million, two hundred nine thousand, six hundred forty-two".