21730764646 has 4 divisors (see below), whose sum is σ = 32596146972. Its totient is φ = 10865382322.

The previous prime is 21730764637. The next prime is 21730764647. The reversal of 21730764646 is 64646703712.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21730764646² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21730764596 and 21730764605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21730764647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5432691160 + ... + 5432691163.

It is an arithmetic number, because the mean of its divisors is an integer number (8149036743).

Almost surely, 2^21730764646 is an apocalyptic number.

21730764646 is a deficient number, since it is larger than the sum of its proper divisors (10865382326).

21730764646 is a wasteful number, since it uses less digits than its factorization.

21730764646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10865382325.

The product of its (nonzero) digits is 1016064, while the sum is 46.

The spelling of 21730764646 in words is "twenty-one billion, seven hundred thirty million, seven hundred sixty-four thousand, six hundred forty-six".