21904145494 has 16 divisors (see below), whose sum is σ = 40963597056. Its totient is φ = 8534082600.

The previous prime is 21904145479. The next prime is 21904145507. The reversal of 21904145494 is 49454140912.

It is a self number, because there is not a number n which added to its sum of digits gives 21904145494.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71117202 + ... + 71117509.

It is an arithmetic number, because the mean of its divisors is an integer number (2560224816).

Almost surely, 2^21904145494 is an apocalyptic number.

21904145494 is a deficient number, since it is larger than the sum of its proper divisors (19059451562).

21904145494 is a wasteful number, since it uses less digits than its factorization.

21904145494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142234731.

The product of its (nonzero) digits is 207360, while the sum is 43.

The spelling of 21904145494 in words is "twenty-one billion, nine hundred four million, one hundred forty-five thousand, four hundred ninety-four".