21155205612354 has 32 divisors (see below), whose sum is σ = 46157628384000. Its totient is φ = 6410555014800.

The previous prime is 21155205612313. The next prime is 21155205612377. The reversal of 21155205612354 is 45321650255112.

It is a happy number.

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 15 ways as a sum of consecutive naturals, for example, 965397 + ... + 6575895.

It is an arithmetic number, because the mean of its divisors is an integer number (1442425887000).

Almost surely, 2^{21155205612354} is an apocalyptic number.

21155205612354 is an abundant number, since it is smaller than the sum of its proper divisors (25002422771646).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21155205612354 is a wasteful number, since it uses less digits than its factorization.

21155205612354 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5667646.

The product of its (nonzero) digits is 360000, while the sum is 42.

Adding to 21155205612354 its reverse (45321650255112), we get a palindrome (66476855867466).

The spelling of 21155205612354 in words is "twenty-one trillion, one hundred fifty-five billion, two hundred five million, six hundred twelve thousand, three hundred fifty-four".