21681488152464 has 40 divisors (see below), whose sum is σ = 64012012641600. Its totient is φ = 6194710900608.

The previous prime is 21681488152463. The next prime is 21681488152501. The reversal of 21681488152464 is 46425188418612.

It is a super-2 number, since 2×21681488152464² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21681488152398 and 21681488152407.

It is not an unprimeable number, because it can be changed into a prime (21681488152463) 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, 32264118939 + ... + 32264119610.

It is an arithmetic number, because the mean of its divisors is an integer number (1600300316040).

Almost surely, 2^{21681488152464} is an apocalyptic number.

21681488152464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21681488152464 is an abundant number, since it is smaller than the sum of its proper divisors (42330524489136).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21681488152464 is a wasteful number, since it uses less digits than its factorization.

21681488152464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64528238567 (or 64528238561 counting only the distinct ones).

The product of its digits is 23592960, while the sum is 60.

The spelling of 21681488152464 in words is "twenty-one trillion, six hundred eighty-one billion, four hundred eighty-eight million, one hundred fifty-two thousand, four hundred sixty-four".