21145345155 has 48 divisors (see below), whose sum is σ = 41064607584. Its totient is φ = 9975191040.

The previous prime is 21145345121. The next prime is 21145345201. The reversal of 21145345155 is 55154354112.

21145345155 is a `hidden beast` number, since 2 + 11 + 453 + 45 + 155 = 666.

It is not a de Polignac number, because 21145345155 - 2¹² = 21145341059 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 558954 + ... + 595583.

It is an arithmetic number, because the mean of its divisors is an integer number (855512658).

Almost surely, 2^21145345155 is an apocalyptic number.

21145345155 is a deficient number, since it is larger than the sum of its proper divisors (19919262429).

21145345155 is a wasteful number, since it uses less digits than its factorization.

21145345155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1154596 (or 1154593 counting only the distinct ones).

The product of its digits is 60000, while the sum is 36.

Adding to 21145345155 its reverse (55154354112), we get a palindrome (76299699267).

The spelling of 21145345155 in words is "twenty-one billion, one hundred forty-five million, three hundred forty-five thousand, one hundred fifty-five".