642978156769 has 16 divisors (see below), whose sum is σ = 704608192512. Its totient is φ = 583132987008.

The previous prime is 642978156739. The next prime is 642978156853. The reversal of 642978156769 is 967651879246.

It is a happy number.

It is not a de Polignac number, because 642978156769 - 2²⁵ = 642944602337 is a prime.

It is a super-2 number, since 2×642978156769² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 642978156698 and 642978156707.

It is not an unprimeable number, because it can be changed into a prime (642978156739) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 630124 + ... + 1297309.

It is an arithmetic number, because the mean of its divisors is an integer number (44038012032).

Almost surely, 2^642978156769 is an apocalyptic number.

It is an amenable number.

642978156769 is a deficient number, since it is larger than the sum of its proper divisors (61630035743).

642978156769 is a wasteful number, since it uses less digits than its factorization.

642978156769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1927896.

The product of its digits is 274337280, while the sum is 70.

The spelling of 642978156769 in words is "six hundred forty-two billion, nine hundred seventy-eight million, one hundred fifty-six thousand, seven hundred sixty-nine".