21090658694 has 24 divisors (see below), whose sum is σ = 38965817880. Its totient is φ = 8507155776.

The previous prime is 21090658691. The next prime is 21090658741. The reversal of 21090658694 is 49685609012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21090658691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6328064 + ... + 6331395.

It is an arithmetic number, because the mean of its divisors is an integer number (1623575745).

Almost surely, 2^21090658694 is an apocalyptic number.

21090658694 is a deficient number, since it is larger than the sum of its proper divisors (17875159186).

21090658694 is a wasteful number, since it uses less digits than its factorization.

21090658694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12659492 (or 12659485 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 50.

The spelling of 21090658694 in words is "twenty-one billion, ninety million, six hundred fifty-eight thousand, six hundred ninety-four".