21312120510 has 24 divisors (see below), whose sum is σ = 55411513560. Its totient is φ = 5683232112.

The previous prime is 21312120461. The next prime is 21312120527. The reversal of 21312120510 is 1502121312.

21312120510 is a `hidden beast` number, since 2 + 1 + 31 + 2 + 120 + 510 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 118400580 + ... + 118400759.

It is an arithmetic number, because the mean of its divisors is an integer number (2308813065).

Almost surely, 2^21312120510 is an apocalyptic number.

21312120510 is an abundant number, since it is smaller than the sum of its proper divisors (34099393050).

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

21312120510 is a wasteful number, since it uses less digits than its factorization.

21312120510 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236801352 (or 236801349 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

Adding to 21312120510 its reverse (1502121312), we get a palindrome (22814241822).

The spelling of 21312120510 in words is "twenty-one billion, three hundred twelve million, one hundred twenty thousand, five hundred ten".