21398494890 has 16 divisors (see below), whose sum is σ = 51356387808. Its totient is φ = 5706265296.

The previous prime is 21398494879. The next prime is 21398494913. The reversal of 21398494890 is 9849489312.

It is a super-2 number, since 2×21398494890² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21398494890.

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, 356641552 + ... + 356641611.

It is an arithmetic number, because the mean of its divisors is an integer number (3209774238).

Almost surely, 2^21398494890 is an apocalyptic number.

21398494890 is an abundant number, since it is smaller than the sum of its proper divisors (29957892918).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21398494890 is a wasteful number, since it uses less digits than its factorization.

21398494890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 713283173.

The product of its (nonzero) digits is 4478976, while the sum is 57.

The spelling of 21398494890 in words is "twenty-one billion, three hundred ninety-eight million, four hundred ninety-four thousand, eight hundred ninety".