21036640155 has 16 divisors (see below), whose sum is σ = 33666184224. Its totient is φ = 11217021440.

The previous prime is 21036640067. The next prime is 21036640159. The reversal of 21036640155 is 55104663012.

It is not a de Polignac number, because 21036640155 - 2¹² = 21036636059 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21036640159) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87486 + ... + 222995.

It is an arithmetic number, because the mean of its divisors is an integer number (2104136514).

Almost surely, 2^21036640155 is an apocalyptic number.

21036640155 is a deficient number, since it is larger than the sum of its proper divisors (12629544069).

21036640155 is a wasteful number, since it uses less digits than its factorization.

21036640155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315006.

The product of its (nonzero) digits is 21600, while the sum is 33.

The spelling of 21036640155 in words is "twenty-one billion, thirty-six million, six hundred forty thousand, one hundred fifty-five".