21398449666 has 16 divisors (see below), whose sum is σ = 35017904448. Its totient is φ = 9725940400.

The previous prime is 21398449621. The next prime is 21398449673. The reversal of 21398449666 is 66694489312.

It is a self number, because there is not a number n which added to its sum of digits gives 21398449666.

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, 596211 + ... + 631081.

It is an arithmetic number, because the mean of its divisors is an integer number (2188619028).

Almost surely, 2^21398449666 is an apocalyptic number.

21398449666 is a deficient number, since it is larger than the sum of its proper divisors (13619454782).

21398449666 is a wasteful number, since it uses less digits than its factorization.

21398449666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62777.

The product of its digits is 13436928, while the sum is 58.

The spelling of 21398449666 in words is "twenty-one billion, three hundred ninety-eight million, four hundred forty-nine thousand, six hundred sixty-six".