21621562356342 has 32 divisors (see below), whose sum is σ = 46635202424160. Its totient is φ = 6643405059840.

The previous prime is 21621562356311. The next prime is 21621562356347. The reversal of 21621562356342 is 24365326512612.

It is a junction number, because it is equal to n+sod(n) for n = 21621562356291 and 21621562356300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621562356347) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 195430959 + ... + 195541562.

It is an arithmetic number, because the mean of its divisors is an integer number (1457350075755).

Almost surely, 2^{21621562356342} is an apocalyptic number.

21621562356342 is an abundant number, since it is smaller than the sum of its proper divisors (25013640067818).

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

21621562356342 is a wasteful number, since it uses less digits than its factorization.

21621562356342 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390973248.

The product of its digits is 3110400, while the sum is 48.

Adding to 21621562356342 its reverse (24365326512612), we get a palindrome (45986888868954).

The spelling of 21621562356342 in words is "twenty-one trillion, six hundred twenty-one billion, five hundred sixty-two million, three hundred fifty-six thousand, three hundred forty-two".