21201345155 has 16 divisors (see below), whose sum is σ = 25684732800. Its totient is φ = 16799682432.

The previous prime is 21201345107. The next prime is 21201345163. The reversal of 21201345155 is 55154310212.

It is a cyclic number.

It is not a de Polignac number, because 21201345155 - 2¹⁸ = 21201083011 is a prime.

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, 206246 + ... + 291444.

It is an arithmetic number, because the mean of its divisors is an integer number (1605295800).

Almost surely, 2^21201345155 is an apocalyptic number.

21201345155 is a deficient number, since it is larger than the sum of its proper divisors (4483387645).

21201345155 is a wasteful number, since it uses less digits than its factorization.

21201345155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85678.

The product of its (nonzero) digits is 6000, while the sum is 29.

Adding to 21201345155 its reverse (55154310212), we get a palindrome (76355655367).

The spelling of 21201345155 in words is "twenty-one billion, two hundred one million, three hundred forty-five thousand, one hundred fifty-five".