21000000122 has 8 divisors (see below), whose sum is σ = 31503553236. Its totient is φ = 10498815712.

The previous prime is 21000000121. The next prime is 21000000143. The reversal of 21000000122 is 22100000012.

It can be written as a sum of positive squares in 2 ways, for example, as 19740531001 + 1259469121 = 140501^2 + 35489^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21000000121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 569843 + ... + 605574.

Almost surely, 2^21000000122 is an apocalyptic number.

21000000122 is a deficient number, since it is larger than the sum of its proper divisors (10503553114).

21000000122 is a wasteful number, since it uses less digits than its factorization.

21000000122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1184352.

The product of its (nonzero) digits is 8, while the sum is 8.

Adding to 21000000122 its reverse (22100000012), we get a palindrome (43100000134).

It can be divided in two parts, 2100000012 and 2, that multiplied together give a palindrome (4200000024).

The spelling of 21000000122 in words is "twenty-one billion, one hundred twenty-two", and thus it is an aban number.