21165400355 has 8 divisors (see below), whose sum is σ = 27707433264. Its totient is φ = 15393018400.

The previous prime is 21165400327. The next prime is 21165400369. The reversal of 21165400355 is 55300456112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21165400355 - 2⁸ = 21165400099 is a prime.

It is a Duffinian 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 7 ways as a sum of consecutive naturals, for example, 192412676 + ... + 192412785.

It is an arithmetic number, because the mean of its divisors is an integer number (3463429158).

Almost surely, 2^21165400355 is an apocalyptic number.

21165400355 is a deficient number, since it is larger than the sum of its proper divisors (6542032909).

21165400355 is a wasteful number, since it uses less digits than its factorization.

21165400355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384825477.

The product of its (nonzero) digits is 18000, while the sum is 32.

Adding to 21165400355 its reverse (55300456112), we get a palindrome (76465856467).

The spelling of 21165400355 in words is "twenty-one billion, one hundred sixty-five million, four hundred thousand, three hundred fifty-five".