21155554087 has 8 divisors (see below), whose sum is σ = 21480301440. Its totient is φ = 20833102200.

The previous prime is 21155554081. The next prime is 21155554093. The reversal of 21155554087 is 78045555112.

It is an interprime number because it is at equal distance from previous prime (21155554081) and next prime (21155554093).

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

It is a cyclic number.

It is not a de Polignac number, because 21155554087 - 2¹¹ = 21155552039 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155554081) 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, 555289 + ... + 592162.

It is an arithmetic number, because the mean of its divisors is an integer number (2685037680).

Almost surely, 2^21155554087 is an apocalyptic number.

21155554087 is a deficient number, since it is larger than the sum of its proper divisors (324747353).

21155554087 is a wasteful number, since it uses less digits than its factorization.

21155554087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1147733.

The product of its (nonzero) digits is 280000, while the sum is 43.

The spelling of 21155554087 in words is "twenty-one billion, one hundred fifty-five million, five hundred fifty-four thousand, eighty-seven".