21021311542 has 48 divisors (see below), whose sum is σ = 42120665280. Its totient is φ = 7759054800.

The previous prime is 21021311527. The next prime is 21021311557. The reversal of 21021311542 is 24511312012.

It is an interprime number because it is at equal distance from previous prime (21021311527) and next prime (21021311557).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 492684 + ... + 533647.

It is an arithmetic number, because the mean of its divisors is an integer number (877513860).

Almost surely, 2^21021311542 is an apocalyptic number.

21021311542 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21021311542 is an abundant number, since it is smaller than the sum of its proper divisors (21099353738).

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

21021311542 is a wasteful number, since it uses less digits than its factorization.

21021311542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1026377 (or 1026370 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

Adding to 21021311542 its reverse (24511312012), we get a palindrome (45532623554).

The spelling of 21021311542 in words is "twenty-one billion, twenty-one million, three hundred eleven thousand, five hundred forty-two".