21978107377990 has 8 divisors (see below), whose sum is σ = 39560593280400. Its totient is φ = 8791242951192.

The previous prime is 21978107377987. The next prime is 21978107378047. The reversal of 21978107377990 is 9977370187912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1098905368890 + ... + 1098905368909.

It is an arithmetic number, because the mean of its divisors is an integer number (4945074160050).

Almost surely, 2^{21978107377990} is an apocalyptic number.

21978107377990 is a deficient number, since it is larger than the sum of its proper divisors (17582485902410).

21978107377990 is a wasteful number, since it uses less digits than its factorization.

21978107377990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2197810737806.

The product of its (nonzero) digits is 84015792, while the sum is 70.

The spelling of 21978107377990 in words is "twenty-one trillion, nine hundred seventy-eight billion, one hundred seven million, three hundred seventy-seven thousand, nine hundred ninety".