21650371649 has 4 divisors (see below), whose sum is σ = 21860569536. Its totient is φ = 21440173764.

The previous prime is 21650371619. The next prime is 21650371679. The reversal of 21650371649 is 94617305612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21650371619) and next prime (21650371679).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21650371649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21650371619) 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, 105098789 + ... + 105098994.

It is an arithmetic number, because the mean of its divisors is an integer number (5465142384).

Almost surely, 2^21650371649 is an apocalyptic number.

It is an amenable number.

21650371649 is a deficient number, since it is larger than the sum of its proper divisors (210197887).

21650371649 is a wasteful number, since it uses less digits than its factorization.

21650371649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210197886.

The product of its (nonzero) digits is 272160, while the sum is 44.

The spelling of 21650371649 in words is "twenty-one billion, six hundred fifty million, three hundred seventy-one thousand, six hundred forty-nine".