21515453521240 has 32 divisors (see below), whose sum is σ = 55325451912480. Its totient is φ = 7376726921472.

The previous prime is 21515453521201. The next prime is 21515453521291. The reversal of 21515453521240 is 4212535451512.

It is a super-2 number, since 2×21515453521240² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 21515453521193 and 21515453521202.

It is a congruent number.

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, 38420452437 + ... + 38420452996.

It is an arithmetic number, because the mean of its divisors is an integer number (1728920372265).

Almost surely, 2^{21515453521240} is an apocalyptic number.

21515453521240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21515453521240 is an abundant number, since it is smaller than the sum of its proper divisors (33809998391240).

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

21515453521240 is a wasteful number, since it uses less digits than its factorization.

21515453521240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76840905451 (or 76840905447 counting only the distinct ones).

The product of its (nonzero) digits is 240000, while the sum is 40.

Adding to 21515453521240 its reverse (4212535451512), we get a palindrome (25727988972752).

The spelling of 21515453521240 in words is "twenty-one trillion, five hundred fifteen billion, four hundred fifty-three million, five hundred twenty-one thousand, two hundred forty".