21501553501145 has 8 divisors (see below), whose sum is σ = 25802427332040. Its totient is φ = 17200867380480.

The previous prime is 21501553501133. The next prime is 21501553501171. The reversal of 21501553501145 is 54110535510512.

It can be written as a sum of positive squares in 4 ways, for example, as 2482953396121 + 19018600105024 = 1575739^2 + 4361032^2 .

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

It is not a de Polignac number, because 21501553501145 - 2⁶ = 21501553501081 is a prime.

It is a super-2 number, since 2×21501553501145² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21501553501099 and 21501553501108.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46675430 + ... + 47133839.

It is an arithmetic number, because the mean of its divisors is an integer number (3225303416505).

Almost surely, 2^{21501553501145} is an apocalyptic number.

It is an amenable number.

21501553501145 is a deficient number, since it is larger than the sum of its proper divisors (4300873830895).

21501553501145 is an equidigital number, since it uses as much as digits as its factorization.

21501553501145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93855115.

The product of its (nonzero) digits is 75000, while the sum is 38.

The spelling of 21501553501145 in words is "twenty-one trillion, five hundred one billion, five hundred fifty-three million, five hundred one thousand, one hundred forty-five".