21106309786 has 16 divisors (see below), whose sum is σ = 31933224000. Its totient is φ = 10462183200.

The previous prime is 21106309739. The next prime is 21106309811. The reversal of 21106309786 is 68790360112.

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, 80670 + ... + 220726.

It is an arithmetic number, because the mean of its divisors is an integer number (1995826500).

Almost surely, 2^21106309786 is an apocalyptic number.

21106309786 is a deficient number, since it is larger than the sum of its proper divisors (10826914214).

21106309786 is a wasteful number, since it uses less digits than its factorization.

21106309786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140709.

The product of its (nonzero) digits is 108864, while the sum is 43.

Adding to 21106309786 its reverse (68790360112), we get a palindrome (89896669898).

The spelling of 21106309786 in words is "twenty-one billion, one hundred six million, three hundred nine thousand, seven hundred eighty-six".