640321421321442 has 128 divisors (see below), whose sum is σ = 1492247083751424. Its totient is φ = 179393545824768.

The previous prime is 640321421321429. The next prime is 640321421321473. The reversal of 640321421321442 is 244123124123046.

It is a super-2 number, since 2×640321421321442² (a number of 30 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 640321421321442.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 706145113 + ... + 707051315.

It is an arithmetic number, because the mean of its divisors is an integer number (11658180341808).

Almost surely, 2^{640321421321442} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640321421321442, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (746123541875712).

640321421321442 is an abundant number, since it is smaller than the sum of its proper divisors (851925662429982).

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

640321421321442 is a wasteful number, since it uses less digits than its factorization.

640321421321442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 907432.

The product of its (nonzero) digits is 221184, while the sum is 39.

Adding to 640321421321442 its reverse (244123124123046), we get a palindrome (884444545444488).

The spelling of 640321421321442 in words is "six hundred forty trillion, three hundred twenty-one billion, four hundred twenty-one million, three hundred twenty-one thousand, four hundred forty-two".