21521225340 has 60 divisors (see below), whose sum is σ = 67512886056. Its totient is φ = 5738992992.

The previous prime is 21521225261. The next prime is 21521225357. The reversal of 21521225340 is 4352212512.

21521225340 is a `hidden beast` number, since 2 + 1 + 5 + 2 + 122 + 534 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6640734 + ... + 6643973.

Almost surely, 2^21521225340 is an apocalyptic number.

21521225340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21521225340 is an abundant number, since it is smaller than the sum of its proper divisors (45991660716).

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

21521225340 is a wasteful number, since it uses less digits than its factorization.

21521225340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13284728 (or 13284717 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

Adding to 21521225340 its reverse (4352212512), we get a palindrome (25873437852).

The spelling of 21521225340 in words is "twenty-one billion, five hundred twenty-one million, two hundred twenty-five thousand, three hundred forty".