21601245 has 16 divisors (see below), whose sum is σ = 34828992. Its totient is φ = 11431680.

The previous prime is 21601189. The next prime is 21601277. The reversal of 21601245 is 54210612.

It is not a de Polignac number, because 21601245 - 2⁸ = 21600989 is a prime.

It is a super-2 number, since 2×21601245² = 933227571100050, which contains 22 as substring.

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3532 + ... + 7461.

It is an arithmetic number, because the mean of its divisors is an integer number (2176812).

Almost surely, 2^21601245 is an apocalyptic number.

It is an amenable number.

21601245 is a deficient number, since it is larger than the sum of its proper divisors (13227747).

21601245 is a wasteful number, since it uses less digits than its factorization.

21601245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11132.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 21601245 is about 4647.7139541930. The cubic root of 21601245 is about 278.5006806344.

Adding to 21601245 its reverse (54210612), we get a palindrome (75811857).

The spelling of 21601245 in words is "twenty-one million, six hundred one thousand, two hundred forty-five".