21405216191950 has 12 divisors (see below), whose sum is σ = 39813702117120. Its totient is φ = 8562086476760.

The previous prime is 21405216191911. The next prime is 21405216191999. The reversal of 21405216191950 is 5919161250412.

It is a self number, because there is not a number n which added to its sum of digits gives 21405216191950.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 214052161870 + ... + 214052161969.

It is an arithmetic number, because the mean of its divisors is an integer number (3317808509760).

Almost surely, 2^{21405216191950} is an apocalyptic number.

21405216191950 is a deficient number, since it is larger than the sum of its proper divisors (18408485925170).

21405216191950 is a wasteful number, since it uses less digits than its factorization.

21405216191950 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 428104323851 (or 428104323846 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 46.

The spelling of 21405216191950 in words is "twenty-one trillion, four hundred five billion, two hundred sixteen million, one hundred ninety-one thousand, nine hundred fifty".