21021034540 has 48 divisors (see below), whose sum is σ = 49817890080. Its totient is φ = 7380423680.

The previous prime is 21021034459. The next prime is 21021034547. The reversal of 21021034540 is 4543012012.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (21021034547) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1641037 + ... + 1653796.

It is an arithmetic number, because the mean of its divisors is an integer number (1037872710).

Almost surely, 2^21021034540 is an apocalyptic number.

21021034540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021034540 is an abundant number, since it is smaller than the sum of its proper divisors (28796855540).

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

21021034540 is a wasteful number, since it uses less digits than its factorization.

21021034540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3294882 (or 3294880 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

Adding to 21021034540 its reverse (4543012012), we get a palindrome (25564046552).

The spelling of 21021034540 in words is "twenty-one billion, twenty-one million, thirty-four thousand, five hundred forty".