20421151535240 has 32 divisors (see below), whose sum is σ = 45949303940760. Its totient is φ = 8168156083200.

The previous prime is 20421151535203. The next prime is 20421151535273. The reversal of 20421151535240 is 4253515112402.

It can be written as a sum of positive squares in 4 ways, for example, as 8541672592996 + 11879478942244 = 2922614^2 + 3446662^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20421151535240.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8428721 + ... + 10577600.

Almost surely, 2^{20421151535240} is an apocalyptic number.

20421151535240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20421151535240 is an abundant number, since it is smaller than the sum of its proper divisors (25528152405520).

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

20421151535240 is a wasteful number, since it uses less digits than its factorization.

20421151535240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19033193 (or 19033189 counting only the distinct ones).

The product of its (nonzero) digits is 48000, while the sum is 35.

Adding to 20421151535240 its reverse (4253515112402), we get a palindrome (24674666647642).

The spelling of 20421151535240 in words is "twenty trillion, four hundred twenty-one billion, one hundred fifty-one million, five hundred thirty-five thousand, two hundred forty".