21542412 has 12 divisors (see below), whose sum is σ = 50265656. Its totient is φ = 7180800.

The previous prime is 21542393. The next prime is 21542413. The reversal of 21542412 is 21424512.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21542413) 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, 897589 + ... + 897612.

Almost surely, 2^21542412 is an apocalyptic number.

It is an amenable number.

21542412 is an abundant number, since it is smaller than the sum of its proper divisors (28723244).

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

21542412 is a wasteful number, since it uses less digits than its factorization.

21542412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1795208 (or 1795206 counting only the distinct ones).

The product of its digits is 640, while the sum is 21.

The square root of 21542412 is about 4641.3803981143. The cubic root of 21542412 is about 278.2476099051.

Adding to 21542412 its reverse (21424512), we get a palindrome (42966924).

The spelling of 21542412 in words is "twenty-one million, five hundred forty-two thousand, four hundred twelve".