21405417420648 has 16 divisors (see below), whose sum is σ = 53513543551680. Its totient is φ = 7135139140208.

The previous prime is 21405417420551. The next prime is 21405417420659. The reversal of 21405417420648 is 84602471450412.

It is a junction number, because it is equal to n+sod(n) for n = 21405417420597 and 21405417420606.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 445946196240 + ... + 445946196287.

It is an arithmetic number, because the mean of its divisors is an integer number (3344596471980).

Almost surely, 2^{21405417420648} is an apocalyptic number.

It is an amenable number.

21405417420648 is an abundant number, since it is smaller than the sum of its proper divisors (32108126131032).

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

21405417420648 is a wasteful number, since it uses less digits than its factorization.

21405417420648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891892392536 (or 891892392532 counting only the distinct ones).

The product of its (nonzero) digits is 1720320, while the sum is 48.

The spelling of 21405417420648 in words is "twenty-one trillion, four hundred five billion, four hundred seventeen million, four hundred twenty thousand, six hundred forty-eight".