21516255261512 has 128 divisors (see below), whose sum is σ = 47578544640000. Its totient is φ = 9018147168000.

The previous prime is 21516255261503. The next prime is 21516255261517.

It is a happy number.

21516255261512 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×21516255261512² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is not an unprimeable number, because it can be changed into a prime (21516255261517) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8883689 + ... + 11043207.

It is an arithmetic number, because the mean of its divisors is an integer number (371707380000).

Almost surely, 2^{21516255261512} is an apocalyptic number.

21516255261512 is a gapful number since it is divisible by the number (22) 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 21516255261512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23789272320000).

21516255261512 is an abundant number, since it is smaller than the sum of its proper divisors (26062289378488).

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

21516255261512 is a wasteful number, since it uses less digits than its factorization.

21516255261512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2159715 (or 2159711 counting only the distinct ones).

The product of its digits is 360000, while the sum is 44.

The spelling of 21516255261512 in words is "twenty-one trillion, five hundred sixteen billion, two hundred fifty-five million, two hundred sixty-one thousand, five hundred twelve".