21151155645 has 32 divisors (see below), whose sum is σ = 38519187840. Its totient is φ = 11005476480.

The previous prime is 21151155643. The next prime is 21151155667. The reversal of 21151155645 is 54655115112.

21151155645 is a `hidden beast` number, since 2 + 1 + 1 + 5 + 1 + 1 + 5 + 5 + 645 = 666.

It is not a de Polignac number, because 21151155645 - 2¹ = 21151155643 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21151155643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1905139 + ... + 1916208.

It is an arithmetic number, because the mean of its divisors is an integer number (1203724620).

Almost surely, 2^21151155645 is an apocalyptic number.

It is an amenable number.

21151155645 is a deficient number, since it is larger than the sum of its proper divisors (17368032195).

21151155645 is a wasteful number, since it uses less digits than its factorization.

21151155645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3821402 (or 3821396 counting only the distinct ones).

The product of its digits is 30000, while the sum is 36.

The spelling of 21151155645 in words is "twenty-one billion, one hundred fifty-one million, one hundred fifty-five thousand, six hundred forty-five".