21354873540 has 192 divisors, whose sum is σ = 80282603520. Its totient is φ = 4096028160.

The previous prime is 21354873523. The next prime is 21354873647. The reversal of 21354873540 is 4537845312.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 21354873492 and 21354873501.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 117720 + ... + 237839.

It is an arithmetic number, because the mean of its divisors is an integer number (418138560).

Almost surely, 2^21354873540 is an apocalyptic number.

21354873540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21354873540 is an abundant number, since it is smaller than the sum of its proper divisors (58927729980).

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

21354873540 is a wasteful number, since it uses less digits than its factorization.

21354873540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355602 (or 355600 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 42.

The spelling of 21354873540 in words is "twenty-one billion, three hundred fifty-four million, eight hundred seventy-three thousand, five hundred forty".