21247157601 has 16 divisors (see below), whose sum is σ = 32147001600. Its totient is φ = 13863392784.

The previous prime is 21247157593. The next prime is 21247157621. The reversal of 21247157601 is 10675174212.

21247157601 is a `hidden beast` number, since 2 + 1 + 2 + 47 + 1 + 5 + 7 + 601 = 666.

It is not a de Polignac number, because 21247157601 - 2³ = 21247157593 is a prime.

It is a super-2 number, since 2×21247157601² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21247157621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8370346 + ... + 8372883.

It is an arithmetic number, because the mean of its divisors is an integer number (2009187600).

Almost surely, 2^21247157601 is an apocalyptic number.

It is an amenable number.

21247157601 is a deficient number, since it is larger than the sum of its proper divisors (10899843999).

21247157601 is a wasteful number, since it uses less digits than its factorization.

21247157601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16743285 (or 16743279 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

It can be divided in two parts, 212471 and 57601, that added together give a palindrome (270072).

The spelling of 21247157601 in words is "twenty-one billion, two hundred forty-seven million, one hundred fifty-seven thousand, six hundred one".