21155526260531 has 4 divisors (see below), whose sum is σ = 22782874434432. Its totient is φ = 19528178086632.

The previous prime is 21155526260483. The next prime is 21155526260537. The reversal of 21155526260531 is 13506262555112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21155526260531 - 2³⁰ = 21154452518707 is a prime.

It is a super-2 number, since 2×21155526260531² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21155526260537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 813674086931 + ... + 813674086956.

It is an arithmetic number, because the mean of its divisors is an integer number (5695718608608).

Almost surely, 2^{21155526260531} is an apocalyptic number.

21155526260531 is a deficient number, since it is larger than the sum of its proper divisors (1627348173901).

21155526260531 is a wasteful number, since it uses less digits than its factorization.

21155526260531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1627348173900.

The product of its (nonzero) digits is 540000, while the sum is 44.

The spelling of 21155526260531 in words is "twenty-one trillion, one hundred fifty-five billion, five hundred twenty-six million, two hundred sixty thousand, five hundred thirty-one".