21640413212 has 24 divisors (see below), whose sum is σ = 41436136560. Its totient is φ = 9807356160.

The previous prime is 21640413169. The next prime is 21640413233. The reversal of 21640413212 is 21231404612.

It is a super-2 number, since 2×21640413212² (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 in 7 ways as a sum of consecutive naturals, for example, 714887 + ... + 744542.

It is an arithmetic number, because the mean of its divisors is an integer number (1726505690).

Almost surely, 2^21640413212 is an apocalyptic number.

21640413212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21640413212 is a deficient number, since it is larger than the sum of its proper divisors (19795723348).

21640413212 is a wasteful number, since it uses less digits than its factorization.

21640413212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1459781 (or 1459779 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 26.

Adding to 21640413212 its reverse (21231404612), we get a palindrome (42871817824).

The spelling of 21640413212 in words is "twenty-one billion, six hundred forty million, four hundred thirteen thousand, two hundred twelve".