642426151640 has 128 divisors (see below), whose sum is σ = 1784641541760. Its totient is φ = 202675544064.

The previous prime is 642426151621. The next prime is 642426151691. The reversal of 642426151640 is 46151624246.

It is a super-2 number, since 2×642426151640² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 875504 + ... + 1432256.

It is an arithmetic number, because the mean of its divisors is an integer number (13942512045).

Almost surely, 2^642426151640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642426151640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (892320770880).

642426151640 is an abundant number, since it is smaller than the sum of its proper divisors (1142215390120).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642426151640 is a wasteful number, since it uses less digits than its factorization.

642426151640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 557101 (or 557097 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 41.

Adding to 642426151640 its reverse (46151624246), we get a palindrome (688577775886).

The spelling of 642426151640 in words is "six hundred forty-two billion, four hundred twenty-six million, one hundred fifty-one thousand, six hundred forty".