21010242155 has 16 divisors (see below), whose sum is σ = 28926175680. Its totient is φ = 14350958592.

The previous prime is 21010242137. The next prime is 21010242173. The reversal of 21010242155 is 55124201012.

It is an interprime number because it is at equal distance from previous prime (21010242137) and next prime (21010242173).

It is a cyclic number.

It is not a de Polignac number, because 21010242155 - 2⁶ = 21010242091 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21010242155.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1158890 + ... + 1176879.

It is an arithmetic number, because the mean of its divisors is an integer number (1807885980).

Almost surely, 2^21010242155 is an apocalyptic number.

21010242155 is a deficient number, since it is larger than the sum of its proper divisors (7915933525).

21010242155 is a wasteful number, since it uses less digits than its factorization.

21010242155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2336038.

The product of its (nonzero) digits is 800, while the sum is 23.

Adding to 21010242155 its reverse (55124201012), we get a palindrome (76134443167).

The spelling of 21010242155 in words is "twenty-one billion, ten million, two hundred forty-two thousand, one hundred fifty-five".