21121042534 has 4 divisors (see below), whose sum is σ = 31681563804. Its totient is φ = 10560521266.

The previous prime is 21121042517. The next prime is 21121042549. The reversal of 21121042534 is 43524012112.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 21121042499 and 21121042508.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5280260632 + ... + 5280260635.

It is an arithmetic number, because the mean of its divisors is an integer number (7920390951).

Almost surely, 2^21121042534 is an apocalyptic number.

21121042534 is a deficient number, since it is larger than the sum of its proper divisors (10560521270).

21121042534 is a wasteful number, since it uses less digits than its factorization.

21121042534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10560521269.

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21121042534 its reverse (43524012112), we get a palindrome (64645054646).

The spelling of 21121042534 in words is "twenty-one billion, one hundred twenty-one million, forty-two thousand, five hundred thirty-four".