21231016163155 has 16 divisors (see below), whose sum is σ = 26977890785184. Its totient is φ = 15984514332160.

The previous prime is 21231016163143. The next prime is 21231016163171. The reversal of 21231016163155 is 55136161013212.

It is not a de Polignac number, because 21231016163155 - 2¹⁹ = 21231015638867 is a prime.

It is a Duffinian number.

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, 8164657 + ... + 10446226.

It is an arithmetic number, because the mean of its divisors is an integer number (1686118174074).

Almost surely, 2^{21231016163155} is an apocalyptic number.

21231016163155 is a deficient number, since it is larger than the sum of its proper divisors (5746874622029).

21231016163155 is a wasteful number, since it uses less digits than its factorization.

21231016163155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18624326.

The product of its (nonzero) digits is 32400, while the sum is 37.

Adding to 21231016163155 its reverse (55136161013212), we get a palindrome (76367177176367).

The spelling of 21231016163155 in words is "twenty-one trillion, two hundred thirty-one billion, sixteen million, one hundred sixty-three thousand, one hundred fifty-five".