21552170247 has 6 divisors (see below), whose sum is σ = 31130912592. Its totient is φ = 14368113492.

The previous prime is 21552170243. The next prime is 21552170251. The reversal of 21552170247 is 74207125512.

21552170247 is a `hidden beast` number, since 21 + 5 + 521 + 70 + 2 + 47 = 666.

It is an interprime number because it is at equal distance from previous prime (21552170243) and next prime (21552170251).

It is not a de Polignac number, because 21552170247 - 2² = 21552170243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21552170243) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1197342783 + ... + 1197342800.

It is an arithmetic number, because the mean of its divisors is an integer number (5188485432).

Almost surely, 2^21552170247 is an apocalyptic number.

21552170247 is a deficient number, since it is larger than the sum of its proper divisors (9578742345).

21552170247 is a wasteful number, since it uses less digits than its factorization.

21552170247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2394685589 (or 2394685586 counting only the distinct ones).

The product of its (nonzero) digits is 39200, while the sum is 36.

Adding to 21552170247 its reverse (74207125512), we get a palindrome (95759295759).

The spelling of 21552170247 in words is "twenty-one billion, five hundred fifty-two million, one hundred seventy thousand, two hundred forty-seven".