21661032123115 has 32 divisors (see below), whose sum is σ = 32418979246080. Its totient is φ = 13498054108800.

The previous prime is 21661032123113. The next prime is 21661032123121. The reversal of 21661032123115 is 51132123016612.

It is not a de Polignac number, because 21661032123115 - 2¹ = 21661032123113 is a prime.

It is a super-3 number, since 3×21661032123115³ (a number of 41 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21661032123113) 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, 9207835 + ... + 11318404.

It is an arithmetic number, because the mean of its divisors is an integer number (1013093101440).

Almost surely, 2^{21661032123115} is an apocalyptic number.

21661032123115 is a deficient number, since it is larger than the sum of its proper divisors (10757947122965).

21661032123115 is a wasteful number, since it uses less digits than its factorization.

21661032123115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20529003.

The product of its (nonzero) digits is 12960, while the sum is 34.

Adding to 21661032123115 its reverse (51132123016612), we get a palindrome (72793155139727).

The spelling of 21661032123115 in words is "twenty-one trillion, six hundred sixty-one billion, thirty-two million, one hundred twenty-three thousand, one hundred fifteen".