21240115501 has 4 divisors (see below), whose sum is σ = 23171035104. Its totient is φ = 19309195900.

The previous prime is 21240115493. The next prime is 21240115529. The reversal of 21240115501 is 10551104212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21240115501 - 2³ = 21240115493 is a prime.

It is a super-2 number, since 2×21240115501² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240110501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 965459785 + ... + 965459806.

It is an arithmetic number, because the mean of its divisors is an integer number (5792758776).

Almost surely, 2^21240115501 is an apocalyptic number.

It is an amenable number.

21240115501 is a deficient number, since it is larger than the sum of its proper divisors (1930919603).

21240115501 is a wasteful number, since it uses less digits than its factorization.

21240115501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1930919602.

The product of its (nonzero) digits is 400, while the sum is 22.

Adding to 21240115501 its reverse (10551104212), we get a palindrome (31791219713).

The spelling of 21240115501 in words is "twenty-one billion, two hundred forty million, one hundred fifteen thousand, five hundred one".