21453748240 has 40 divisors (see below), whose sum is σ = 50346152640. Its totient is φ = 8501294976.

The previous prime is 21453748223. The next prime is 21453748241. The reversal of 21453748240 is 4284735412.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 21453748193 and 21453748202.

It is not an unprimeable number, because it can be changed into a prime (21453748241) 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, 1244580 + ... + 1261699.

It is an arithmetic number, because the mean of its divisors is an integer number (1258653816).

Almost surely, 2^21453748240 is an apocalyptic number.

21453748240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21453748240 is an abundant number, since it is smaller than the sum of its proper divisors (28892404400).

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

21453748240 is a wasteful number, since it uses less digits than its factorization.

21453748240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2506399 (or 2506393 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 40.

The spelling of 21453748240 in words is "twenty-one billion, four hundred fifty-three million, seven hundred forty-eight thousand, two hundred forty".