20261312642 has 4 divisors (see below), whose sum is σ = 30391968966. Its totient is φ = 10130656320.

The previous prime is 20261312633. The next prime is 20261312647. The reversal of 20261312642 is 24621316202.

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

It can be written as a sum of positive squares in only one way, i.e., 19022202241 + 1239110401 = 137921^2 + 35201^2 .

It is not an unprimeable number, because it can be changed into a prime (20261312647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5065328159 + ... + 5065328162.

Almost surely, 2^20261312642 is an apocalyptic number.

20261312642 is a deficient number, since it is larger than the sum of its proper divisors (10130656324).

20261312642 is a wasteful number, since it uses less digits than its factorization.

20261312642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10130656323.

The product of its (nonzero) digits is 6912, while the sum is 29.

Adding to 20261312642 its reverse (24621316202), we get a palindrome (44882628844).

The spelling of 20261312642 in words is "twenty billion, two hundred sixty-one million, three hundred twelve thousand, six hundred forty-two".