642525371521 has 8 divisors (see below), whose sum is σ = 700952825088. Its totient is φ = 584100594000.

The previous prime is 642525371519. The next prime is 642525371549. The reversal of 642525371521 is 125173525246.

642525371521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 642525371521 - 2¹ = 642525371519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642525371021) 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, 149425 + ... + 1143406.

It is an arithmetic number, because the mean of its divisors is an integer number (87619103136).

Almost surely, 2^642525371521 is an apocalyptic number.

It is an amenable number.

642525371521 is a deficient number, since it is larger than the sum of its proper divisors (58427453567).

642525371521 is a wasteful number, since it uses less digits than its factorization.

642525371521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1338023.

The product of its digits is 504000, while the sum is 43.

Adding to 642525371521 its reverse (125173525246), we get a palindrome (767698896767).

The spelling of 642525371521 in words is "six hundred forty-two billion, five hundred twenty-five million, three hundred seventy-one thousand, five hundred twenty-one".