21245537247 has 8 divisors (see below), whose sum is σ = 30902599680. Its totient is φ = 12876083160.

The previous prime is 21245537237. The next prime is 21245537267. The reversal of 21245537247 is 74273554212.

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

It is not a de Polignac number, because 21245537247 - 2¹² = 21245533151 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21245537199 and 21245537208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21245537227) 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, 321902047 + ... + 321902112.

It is an arithmetic number, because the mean of its divisors is an integer number (3862824960).

Almost surely, 2^21245537247 is an apocalyptic number.

21245537247 is a deficient number, since it is larger than the sum of its proper divisors (9657062433).

21245537247 is a wasteful number, since it uses less digits than its factorization.

21245537247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643804173.

The product of its digits is 470400, while the sum is 42.

The spelling of 21245537247 in words is "twenty-one billion, two hundred forty-five million, five hundred thirty-seven thousand, two hundred forty-seven".