21155240122 has 8 divisors (see below), whose sum is σ = 32331593556. Its totient is φ = 10378042272.

The previous prime is 21155240089. The next prime is 21155240149. The reversal of 21155240122 is 22104255112.

It can be written as a sum of positive squares in 2 ways, for example, as 20701166641 + 454073481 = 143879^2 + 21309^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99788763 + ... + 99788974.

Almost surely, 2^21155240122 is an apocalyptic number.

21155240122 is a deficient number, since it is larger than the sum of its proper divisors (11176353434).

21155240122 is a wasteful number, since it uses less digits than its factorization.

21155240122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199577792.

The product of its (nonzero) digits is 1600, while the sum is 25.

Adding to 21155240122 its reverse (22104255112), we get a palindrome (43259495234).

The spelling of 21155240122 in words is "twenty-one billion, one hundred fifty-five million, two hundred forty thousand, one hundred twenty-two".