4021121221520 has 80 divisors (see below), whose sum is σ = 10072213097520. Its totient is φ = 1484140050432.

The previous prime is 4021121221519. The next prime is 4021121221541. The reversal of 4021121221520 is 251221211204.

It can be written as a sum of positive squares in 8 ways, for example, as 264595014544 + 3756526206976 = 514388^2 + 1938176^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×4021121221520² (a number of 26 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1903226 + ... + 3415334.

It is an arithmetic number, because the mean of its divisors is an integer number (125902663719).

Almost surely, 2^{4021121221520} is an apocalyptic number.

4021121221520 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 4021121221520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5036106548760).

4021121221520 is an abundant number, since it is smaller than the sum of its proper divisors (6051091876000).

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

4021121221520 is a wasteful number, since it uses less digits than its factorization.

4021121221520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1514692 (or 1514686 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 23.

Adding to 4021121221520 its reverse (251221211204), we get a palindrome (4272342432724).

The spelling of 4021121221520 in words is "four trillion, twenty-one billion, one hundred twenty-one million, two hundred twenty-one thousand, five hundred twenty".