73661557 has 2 divisors, whose sum is σ = 73661558. Its totient is φ = 73661556.

The previous prime is 73661531. The next prime is 73661563. The reversal of 73661557 is 75516637.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64625521 + 9036036 = 8039^2 + 3006^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-73661557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (73661057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36830778 + 36830779.

It is an arithmetic number, because the mean of its divisors is an integer number (36830779).

Almost surely, 2^73661557 is an apocalyptic number.

It is an amenable number.

73661557 is a deficient number, since it is larger than the sum of its proper divisors (1).

73661557 is an equidigital number, since it uses as much as digits as its factorization.

73661557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 132300, while the sum is 40.

The square root of 73661557 is about 8582.6311233794. The cubic root of 73661557 is about 419.1926231785.

The spelling of 73661557 in words is "seventy-three million, six hundred sixty-one thousand, five hundred fifty-seven".