21000153451440 has 80 divisors (see below), whose sum is σ = 65102530323168. Its totient is φ = 5599864178688.

The previous prime is 21000153451331. The next prime is 21000153451523. The reversal of 21000153451440 is 4415435100012.

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

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21000153451398 and 21000153451407.

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, 6328914 + ... + 9058446.

Almost surely, 2^{21000153451440} is an apocalyptic number.

21000153451440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000153451440 is an abundant number, since it is smaller than the sum of its proper divisors (44102376871728).

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

21000153451440 is a wasteful number, since it uses less digits than its factorization.

21000153451440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2761606 (or 2761600 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

Adding to 21000153451440 its reverse (4415435100012), we get a palindrome (25415588551452).

The spelling of 21000153451440 in words is "twenty-one trillion, one hundred fifty-three million, four hundred fifty-one thousand, four hundred forty".