21555113402 has 8 divisors (see below), whose sum is σ = 32383113012. Its totient is φ = 10760742400.

The previous prime is 21555113387. The next prime is 21555113429. The reversal of 21555113402 is 20431155512.

It can be written as a sum of positive squares in 2 ways, for example, as 18103433401 + 3451680001 = 134549^2 + 58751^2 .

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

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 3 ways as a sum of consecutive naturals, for example, 8405549 + ... + 8408112.

Almost surely, 2^21555113402 is an apocalyptic number.

21555113402 is a deficient number, since it is larger than the sum of its proper divisors (10827999610).

21555113402 is a wasteful number, since it uses less digits than its factorization.

21555113402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16814304.

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

Adding to 21555113402 its reverse (20431155512), we get a palindrome (41986268914).

The spelling of 21555113402 in words is "twenty-one billion, five hundred fifty-five million, one hundred thirteen thousand, four hundred two".