21025616016531 has 24 divisors (see below), whose sum is σ = 32640199114944. Its totient is φ = 12003938931600.

The previous prime is 21025616016479. The next prime is 21025616016541. The reversal of 21025616016531 is 13561061652012.

It is not a de Polignac number, because 21025616016531 - 2⁶ = 21025616016467 is a prime.

It is a super-2 number, since 2×21025616016531² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21025616016531.

It is not an unprimeable number, because it can be changed into a prime (21025616016541) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 63517645 + ... + 63847806.

It is an arithmetic number, because the mean of its divisors is an integer number (1360008296456).

Almost surely, 2^{21025616016531} is an apocalyptic number.

21025616016531 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21025616016531 is a deficient number, since it is larger than the sum of its proper divisors (11614583098413).

21025616016531 is a wasteful number, since it uses less digits than its factorization.

21025616016531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127366591 (or 127366584 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 39.

Adding to 21025616016531 its reverse (13561061652012), we get a palindrome (34586677668543).

The spelling of 21025616016531 in words is "twenty-one trillion, twenty-five billion, six hundred sixteen million, sixteen thousand, five hundred thirty-one".