21101308646 has 16 divisors (see below), whose sum is σ = 36030693888. Its totient is φ = 9174481800.

The previous prime is 21101308621. The next prime is 21101308649. The reversal of 21101308646 is 64680310112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101308649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20850590 + ... + 20851601.

It is an arithmetic number, because the mean of its divisors is an integer number (2251918368).

Almost surely, 2^21101308646 is an apocalyptic number.

21101308646 is a deficient number, since it is larger than the sum of its proper divisors (14929385242).

21101308646 is a wasteful number, since it uses less digits than its factorization.

21101308646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41702227.

The product of its (nonzero) digits is 6912, while the sum is 32.

Adding to 21101308646 its reverse (64680310112), we get a palindrome (85781618758).

The spelling of 21101308646 in words is "twenty-one billion, one hundred one million, three hundred eight thousand, six hundred forty-six".