55721131 has 2 divisors, whose sum is σ = 55721132. Its totient is φ = 55721130.

The previous prime is 55721117. The next prime is 55721161. The reversal of 55721131 is 13112755.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 55721131 - 2⁹ = 55720619 is a prime.

It is a super-2 number, since 2×55721131² = 6209688879838322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 55721096 and 55721105.

It is not a weakly prime, because it can be changed into another prime (55721161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27860565 + 27860566.

It is an arithmetic number, because the mean of its divisors is an integer number (27860566).

Almost surely, 2^55721131 is an apocalyptic number.

55721131 is a deficient number, since it is larger than the sum of its proper divisors (1).

55721131 is an equidigital number, since it uses as much as digits as its factorization.

55721131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1050, while the sum is 25.

The square root of 55721131 is about 7464.6587999720. The cubic root of 55721131 is about 381.9501113545.

Adding to 55721131 its reverse (13112755), we get a palindrome (68833886).

The spelling of 55721131 in words is "fifty-five million, seven hundred twenty-one thousand, one hundred thirty-one".