20001355542 has 128 divisors (see below), whose sum is σ = 56124057600. Its totient is φ = 5144629248.

The previous prime is 20001355513. The next prime is 20001355547. The reversal of 20001355542 is 24555310002.

It is a happy number.

It is a super-2 number, since 2×20001355542² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001355547) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 80134 + ... + 215462.

It is an arithmetic number, because the mean of its divisors is an integer number (438469200).

Almost surely, 2^20001355542 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20001355542, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28062028800).

20001355542 is an abundant number, since it is smaller than the sum of its proper divisors (36122702058).

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

20001355542 is a wasteful number, since it uses less digits than its factorization.

20001355542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135387 (or 135381 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 27.

Adding to 20001355542 its reverse (24555310002), we get a palindrome (44556665544).

The spelling of 20001355542 in words is "twenty billion, one million, three hundred fifty-five thousand, five hundred forty-two".