21100500655 has 16 divisors (see below), whose sum is σ = 27613514880. Its totient is φ = 15384665088.

The previous prime is 21100500581. The next prime is 21100500671. The reversal of 21100500655 is 55600500112.

It is not a de Polignac number, because 21100500655 - 2⁷ = 21100500527 is a prime.

It is a super-2 number, since 2×21100500655² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2049442 + ... + 2059711.

It is an arithmetic number, because the mean of its divisors is an integer number (1725844680).

Almost surely, 2^21100500655 is an apocalyptic number.

21100500655 is a deficient number, since it is larger than the sum of its proper divisors (6513014225).

21100500655 is a wasteful number, since it uses less digits than its factorization.

21100500655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4109250.

The product of its (nonzero) digits is 1500, while the sum is 25.

The spelling of 21100500655 in words is "twenty-one billion, one hundred million, five hundred thousand, six hundred fifty-five".