21012545412 has 18 divisors (see below), whose sum is σ = 53115045438. Its totient is φ = 7004181792.

The previous prime is 21012545401. The next prime is 21012545419. The reversal of 21012545412 is 21454521012.

It is a happy number.

21012545412 is a `hidden beast` number, since 2 + 101 + 2 + 545 + 4 + 12 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19865774916 + 1146770496 = 140946^2 + 33864^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21012545419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 291840873 + ... + 291840944.

Almost surely, 2^21012545412 is an apocalyptic number.

It is an amenable number.

21012545412 is an abundant number, since it is smaller than the sum of its proper divisors (32102500026).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21012545412 is a wasteful number, since it uses less digits than its factorization.

21012545412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 583681827 (or 583681822 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The spelling of 21012545412 in words is "twenty-one billion, twelve million, five hundred forty-five thousand, four hundred twelve".