21121544212 has 6 divisors (see below), whose sum is σ = 36962702378. Its totient is φ = 10560772104.

The previous prime is 21121544189. The next prime is 21121544251. The reversal of 21121544212 is 21244512112.

It can be written as a sum of positive squares in only one way, i.e., 16056944656 + 5064599556 = 126716^2 + 71166^2 .

It is a super-2 number, since 2×21121544212² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640193023 + ... + 2640193030.

Almost surely, 2^21121544212 is an apocalyptic number.

It is an amenable number.

21121544212 is a deficient number, since it is larger than the sum of its proper divisors (15841158166).

21121544212 is a wasteful number, since it uses less digits than its factorization.

21121544212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5280386057 (or 5280386055 counting only the distinct ones).

The product of its digits is 1280, while the sum is 25.

The spelling of 21121544212 in words is "twenty-one billion, one hundred twenty-one million, five hundred forty-four thousand, two hundred twelve".