21152060664 has 32 divisors (see below), whose sum is σ = 60434459520. Its totient is φ = 6043445856.

The previous prime is 21152060639. The next prime is 21152060689. The reversal of 21152060664 is 46606025112.

It is an interprime number because it is at equal distance from previous prime (21152060639) and next prime (21152060689).

It is a super-2 number, since 2×21152060664² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62952394 + ... + 62952729.

It is an arithmetic number, because the mean of its divisors is an integer number (1888576860).

Almost surely, 2^21152060664 is an apocalyptic number.

21152060664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21152060664 is an abundant number, since it is smaller than the sum of its proper divisors (39282398856).

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

21152060664 is a wasteful number, since it uses less digits than its factorization.

21152060664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125905139 (or 125905135 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

Adding to 21152060664 its reverse (46606025112), we get a palindrome (67758085776).

The spelling of 21152060664 in words is "twenty-one billion, one hundred fifty-two million, sixty thousand, six hundred sixty-four".