55163721 has 8 divisors (see below), whose sum is σ = 73713024. Its totient is φ = 36695120.

The previous prime is 55163699. The next prime is 55163749. The reversal of 55163721 is 12736155.

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

It is a cyclic number.

It is not a de Polignac number, because 55163721 - 2¹⁸ = 54901577 is a prime.

It is a super-2 number, since 2×55163721² = 6086072229131682, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (55163321) 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, 18561 + ... + 21326.

It is an arithmetic number, because the mean of its divisors is an integer number (9214128).

Almost surely, 2^55163721 is an apocalyptic number.

It is an amenable number.

55163721 is a deficient number, since it is larger than the sum of its proper divisors (18549303).

55163721 is a wasteful number, since it uses less digits than its factorization.

55163721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40351.

The product of its digits is 6300, while the sum is 30.

The square root of 55163721 is about 7427.2283524879. The cubic root of 55163721 is about 380.6722196535.

Adding to 55163721 its reverse (12736155), we get a palindrome (67899876).

The spelling of 55163721 in words is "fifty-five million, one hundred sixty-three thousand, seven hundred twenty-one".