21521240111 has 8 divisors (see below), whose sum is σ = 24609699840. Its totient is φ = 18436279608.

The previous prime is 21521240107. The next prime is 21521240129. The reversal of 21521240111 is 11104212512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21521240111 - 2² = 21521240107 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521240101) 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, 861611 + ... + 886236.

It is an arithmetic number, because the mean of its divisors is an integer number (3076212480).

Almost surely, 2^21521240111 is an apocalyptic number.

21521240111 is a deficient number, since it is larger than the sum of its proper divisors (3088459729).

21521240111 is a wasteful number, since it uses less digits than its factorization.

21521240111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1749613.

The product of its (nonzero) digits is 160, while the sum is 20.

Adding to 21521240111 its reverse (11104212512), we get a palindrome (32625452623).

The spelling of 21521240111 in words is "twenty-one billion, five hundred twenty-one million, two hundred forty thousand, one hundred eleven".