21248317766 has 40 divisors (see below), whose sum is σ = 36236868864. Its totient is φ = 9289280880.

The previous prime is 21248317733. The next prime is 21248317771. The reversal of 21248317766 is 66771384212.

It is a super-2 number, since 2×21248317766² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21248317766.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3385211 + ... + 3391481.

Almost surely, 2^21248317766 is an apocalyptic number.

21248317766 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21248317766 is a deficient number, since it is larger than the sum of its proper divisors (14988551098).

21248317766 is an frugal number, since it uses more digits than its factorization.

21248317766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6362 (or 6305 counting only the distinct ones).

The product of its digits is 677376, while the sum is 47.

The spelling of 21248317766 in words is "twenty-one billion, two hundred forty-eight million, three hundred seventeen thousand, seven hundred sixty-six".