21456020621 has 8 divisors (see below), whose sum is σ = 24522699840. Its totient is φ = 18389724768.

The previous prime is 21456020611. The next prime is 21456020639. The reversal of 21456020621 is 12602065412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21456020621 - 2¹⁰ = 21456019597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21456020611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36230 + ... + 210296.

It is an arithmetic number, because the mean of its divisors is an integer number (3065337480).

Almost surely, 2^21456020621 is an apocalyptic number.

It is an amenable number.

21456020621 is a deficient number, since it is larger than the sum of its proper divisors (3066679219).

21456020621 is a wasteful number, since it uses less digits than its factorization.

21456020621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191683.

The product of its (nonzero) digits is 5760, while the sum is 29.

The spelling of 21456020621 in words is "twenty-one billion, four hundred fifty-six million, twenty thousand, six hundred twenty-one".