21378104990 has 64 divisors (see below), whose sum is σ = 43855644672. Its totient is φ = 7432348800.

The previous prime is 21378104987. The next prime is 21378105029. The reversal of 21378104990 is 9940187312.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 245264 + ... + 320796.

It is an arithmetic number, because the mean of its divisors is an integer number (685244448).

Almost surely, 2^21378104990 is an apocalyptic number.

21378104990 is an abundant number, since it is smaller than the sum of its proper divisors (22477539682).

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

21378104990 is a wasteful number, since it uses less digits than its factorization.

21378104990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75665.

The product of its (nonzero) digits is 108864, while the sum is 44.

The spelling of 21378104990 in words is "twenty-one billion, three hundred seventy-eight million, one hundred four thousand, nine hundred ninety".