21009783670 has 8 divisors (see below), whose sum is σ = 37817610624. Its totient is φ = 8403913464.

The previous prime is 21009783611. The next prime is 21009783673. The reversal of 21009783670 is 7638790012.

It is a happy number.

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

It is a super-2 number, since 2×21009783670² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21009783673) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1050489174 + ... + 1050489193.

It is an arithmetic number, because the mean of its divisors is an integer number (4727201328).

Almost surely, 2^21009783670 is an apocalyptic number.

21009783670 is a deficient number, since it is larger than the sum of its proper divisors (16807826954).

21009783670 is a wasteful number, since it uses less digits than its factorization.

21009783670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2100978374.

The product of its (nonzero) digits is 127008, while the sum is 43.

The spelling of 21009783670 in words is "twenty-one billion, nine million, seven hundred eighty-three thousand, six hundred seventy".