21003720240 has 80 divisors (see below), whose sum is σ = 68538470400. Its totient is φ = 5306201856.

The previous prime is 21003720209. The next prime is 21003720251. The reversal of 21003720240 is 4202730012.

It is a tau number, because it is divible by the number of its divisors (80).

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, 2298480 + ... + 2307599.

It is an arithmetic number, because the mean of its divisors is an integer number (856730880).

Almost surely, 2^21003720240 is an apocalyptic number.

21003720240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21003720240 is an abundant number, since it is smaller than the sum of its proper divisors (47534750160).

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

21003720240 is a wasteful number, since it uses less digits than its factorization.

21003720240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4606114 (or 4606108 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 21.

The spelling of 21003720240 in words is "twenty-one billion, three million, seven hundred twenty thousand, two hundred forty".