21549399155 has 12 divisors (see below), whose sum is σ = 27469893360. Its totient is φ = 16225428864.

The previous prime is 21549399107. The next prime is 21549399163. The reversal of 21549399155 is 55199394512.

It is not a de Polignac number, because 21549399155 - 2¹⁸ = 21549137011 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21549399097 and 21549399106.

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 11 ways as a sum of consecutive naturals, for example, 7455095 + ... + 7457984.

It is an arithmetic number, because the mean of its divisors is an integer number (2289157780).

Almost surely, 2^21549399155 is an apocalyptic number.

21549399155 is a deficient number, since it is larger than the sum of its proper divisors (5920494205).

21549399155 is a wasteful number, since it uses less digits than its factorization.

21549399155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14913118 (or 14913101 counting only the distinct ones).

The product of its digits is 2187000, while the sum is 53.

The spelling of 21549399155 in words is "twenty-one billion, five hundred forty-nine million, three hundred ninety-nine thousand, one hundred fifty-five".