21405105243442 has 8 divisors (see below), whose sum is σ = 32107843249776. Its totient is φ = 10702490826852.

The previous prime is 21405105243437. The next prime is 21405105243479. The reversal of 21405105243442 is 24434250150412.

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

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, 30463228 + ... + 31157959.

It is an arithmetic number, because the mean of its divisors is an integer number (4013480406222).

Almost surely, 2^{21405105243442} is an apocalyptic number.

21405105243442 is a deficient number, since it is larger than the sum of its proper divisors (10702738006334).

21405105243442 is a wasteful number, since it uses less digits than its factorization.

21405105243442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61794872.

The product of its (nonzero) digits is 153600, while the sum is 37.

Adding to 21405105243442 its reverse (24434250150412), we get a palindrome (45839355393854).

The spelling of 21405105243442 in words is "twenty-one trillion, four hundred five billion, one hundred five million, two hundred forty-three thousand, four hundred forty-two".