21061515100216 has 8 divisors (see below), whose sum is σ = 39490340812920. Its totient is φ = 10530757550104.

The previous prime is 21061515100181. The next prime is 21061515100243. The reversal of 21061515100216 is 61200151516012.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1316344693756 + ... + 1316344693771.

It is an arithmetic number, because the mean of its divisors is an integer number (4936292601615).

Almost surely, 2^{21061515100216} is an apocalyptic number.

It is an amenable number.

21061515100216 is a deficient number, since it is larger than the sum of its proper divisors (18428825712704).

21061515100216 is a wasteful number, since it uses less digits than its factorization.

21061515100216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2632689387533 (or 2632689387529 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 31.

Adding to 21061515100216 its reverse (61200151516012), we get a palindrome (82261666616228).

The spelling of 21061515100216 in words is "twenty-one trillion, sixty-one billion, five hundred fifteen million, one hundred thousand, two hundred sixteen".