21354342624 has 36 divisors (see below), whose sum is σ = 60726412656. Its totient is φ = 7118114112.

The previous prime is 21354342613. The next prime is 21354342629. The reversal of 21354342624 is 42624345312.

21354342624 is a `hidden beast` number, since 2 + 13 + 543 + 42 + 62 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354342629) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 37073224 + ... + 37073799.

It is an arithmetic number, because the mean of its divisors is an integer number (1686844796).

Almost surely, 2^21354342624 is an apocalyptic number.

21354342624 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21354342624 is an abundant number, since it is smaller than the sum of its proper divisors (39372070032).

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

21354342624 is a wasteful number, since it uses less digits than its factorization.

21354342624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74147039 (or 74147028 counting only the distinct ones).

The product of its digits is 138240, while the sum is 36.

Adding to 21354342624 its reverse (42624345312), we get a palindrome (63978687936).

The spelling of 21354342624 in words is "twenty-one billion, three hundred fifty-four million, three hundred forty-two thousand, six hundred twenty-four".