21155003412 has 12 divisors (see below), whose sum is σ = 49361674656. Its totient is φ = 7051667800.

The previous prime is 21155003369. The next prime is 21155003431. The reversal of 21155003412 is 21430055112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 881458464 + ... + 881458487.

It is an arithmetic number, because the mean of its divisors is an integer number (4113472888).

Almost surely, 2^21155003412 is an apocalyptic number.

It is an amenable number.

21155003412 is an abundant number, since it is smaller than the sum of its proper divisors (28206671244).

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

21155003412 is a wasteful number, since it uses less digits than its factorization.

21155003412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1762916958 (or 1762916956 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

Adding to 21155003412 its reverse (21430055112), we get a palindrome (42585058524).

The spelling of 21155003412 in words is "twenty-one billion, one hundred fifty-five million, three thousand, four hundred twelve".