21221550061265 has 32 divisors (see below), whose sum is σ = 26974718908800. Its totient is φ = 15982839544320.

The previous prime is 21221550061249. The next prime is 21221550061273. The reversal of 21221550061265 is 56216005512212.

It is not a de Polignac number, because 21221550061265 - 2⁴ = 21221550061249 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10445285 + ... + 12310445.

It is an arithmetic number, because the mean of its divisors is an integer number (842959965900).

Almost surely, 2^{21221550061265} is an apocalyptic number.

It is an amenable number.

21221550061265 is a deficient number, since it is larger than the sum of its proper divisors (5753168847535).

21221550061265 is a wasteful number, since it uses less digits than its factorization.

21221550061265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1865937.

The product of its (nonzero) digits is 72000, while the sum is 38.

Adding to 21221550061265 its reverse (56216005512212), we get a palindrome (77437555573477).

The spelling of 21221550061265 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred fifty million, sixty-one thousand, two hundred sixty-five".