21500123101555 has 8 divisors (see below), whose sum is σ = 29485883110752. Its totient is φ = 14742941555328.

The previous prime is 21500123101553. The next prime is 21500123101601. The reversal of 21500123101555 is 55510132100512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21500123101555 - 2¹ = 21500123101553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21500123101553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 307144615702 + ... + 307144615771.

It is an arithmetic number, because the mean of its divisors is an integer number (3685735388844).

Almost surely, 2^{21500123101555} is an apocalyptic number.

21500123101555 is a deficient number, since it is larger than the sum of its proper divisors (7985760009197).

21500123101555 is an equidigital number, since it uses as much as digits as its factorization.

21500123101555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 614289231485.

The product of its (nonzero) digits is 7500, while the sum is 31.

The spelling of 21500123101555 in words is "twenty-one trillion, five hundred billion, one hundred twenty-three million, one hundred one thousand, five hundred fifty-five".