21152999379121 has 9 divisors (see below), whose sum is σ = 21190701937899. Its totient is φ = 21115363806384.

The previous prime is 21152999379041. The next prime is 21152999379139. The reversal of 21152999379121 is 12197399925112.

The square root of 21152999379121 is 4599239.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 139356623025 + 21013642756096 = 373305^2 + 4584064^2 .

It is not a de Polignac number, because 21152999379121 - 2³⁷ = 21015560425649 is a prime.

It is a super-2 number, since 2×21152999379121² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21152999379121.

It is not an unprimeable number, because it can be changed into a prime (21152999379821) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2791734285 + ... + 2791741861.

Almost surely, 2^{21152999379121} is an apocalyptic number.

21152999379121 is the 4599239-th square number.

21152999379121 is the 2299620-th centered octagonal number.

It is an amenable number.

21152999379121 is a deficient number, since it is larger than the sum of its proper divisors (37702558778).

21152999379121 is an frugal number, since it uses more digits than its factorization.

21152999379121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16368 (or 8184 counting only the distinct ones).

The product of its digits is 5511240, while the sum is 61.

The spelling of 21152999379121 in words is "twenty-one trillion, one hundred fifty-two billion, nine hundred ninety-nine million, three hundred seventy-nine thousand, one hundred twenty-one".