21015705122 has 8 divisors (see below), whose sum is σ = 31524585372. Its totient is φ = 10507510000.

The previous prime is 21015705121. The next prime is 21015705127. The reversal of 21015705122 is 22150751012.

It can be written as a sum of positive squares in 2 ways, for example, as 20701742161 + 313962961 = 143881^2 + 17719^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21015705091 and 21015705100.

It is not an unprimeable number, because it can be changed into a prime (21015705121) 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, 86129 + ... + 222372.

Almost surely, 2^21015705122 is an apocalyptic number.

21015705122 is a deficient number, since it is larger than the sum of its proper divisors (10508880250).

21015705122 is a wasteful number, since it uses less digits than its factorization.

21015705122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342564.

The product of its (nonzero) digits is 1400, while the sum is 26.

The spelling of 21015705122 in words is "twenty-one billion, fifteen million, seven hundred five thousand, one hundred twenty-two".