21240721460 has 48 divisors (see below), whose sum is σ = 50986137216. Its totient is φ = 7281332352.

The previous prime is 21240721429. The next prime is 21240721477. The reversal of 21240721460 is 6412704212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1439279 + ... + 1453961.

It is an arithmetic number, because the mean of its divisors is an integer number (1062211192).

Almost surely, 2^21240721460 is an apocalyptic number.

21240721460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21240721460 is an abundant number, since it is smaller than the sum of its proper divisors (29745415756).

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

21240721460 is a wasteful number, since it uses less digits than its factorization.

21240721460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25032 (or 25030 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 29.

The spelling of 21240721460 in words is "twenty-one billion, two hundred forty million, seven hundred twenty-one thousand, four hundred sixty".