21121512460 has 24 divisors (see below), whose sum is σ = 44378515440. Its totient is φ = 8444159424.

The previous prime is 21121512449. The next prime is 21121512463. The reversal of 21121512460 is 6421512112.

It is a super-2 number, since 2×21121512460² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121512463) 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, 238755 + ... + 315034.

It is an arithmetic number, because the mean of its divisors is an integer number (1849104810).

Almost surely, 2^21121512460 is an apocalyptic number.

21121512460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121512460 is an abundant number, since it is smaller than the sum of its proper divisors (23257002980).

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

21121512460 is a wasteful number, since it uses less digits than its factorization.

21121512460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555705 (or 555703 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 25.

The spelling of 21121512460 in words is "twenty-one billion, one hundred twenty-one million, five hundred twelve thousand, four hundred sixty".