21408927641 has 4 divisors (see below), whose sum is σ = 21410266752. Its totient is φ = 21407588532.

The previous prime is 21408927637. The next prime is 21408927691. The reversal of 21408927641 is 14672980412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21408927641 - 2² = 21408927637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21408927592 and 21408927601.

It is not an unprimeable number, because it can be changed into a prime (21408927691) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 645281 + ... + 677646.

It is an arithmetic number, because the mean of its divisors is an integer number (5352566688).

Almost surely, 2^21408927641 is an apocalyptic number.

It is an amenable number.

21408927641 is a deficient number, since it is larger than the sum of its proper divisors (1339111).

21408927641 is a wasteful number, since it uses less digits than its factorization.

21408927641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1339110.

The product of its (nonzero) digits is 193536, while the sum is 44.

The spelling of 21408927641 in words is "twenty-one billion, four hundred eight million, nine hundred twenty-seven thousand, six hundred forty-one".