45551981 has 2 divisors, whose sum is σ = 45551982. Its totient is φ = 45551980.

The previous prime is 45551969. The next prime is 45551999. The reversal of 45551981 is 18915554.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45292900 + 259081 = 6730^2 + 509^2 .

It is a cyclic number.

It is not a de Polignac number, because 45551981 - 2⁶ = 45551917 is a prime.

It is a super-2 number, since 2×45551981² = 4149965946048722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (45551941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22775990 + 22775991.

It is an arithmetic number, because the mean of its divisors is an integer number (22775991).

Almost surely, 2^45551981 is an apocalyptic number.

It is an amenable number.

45551981 is a deficient number, since it is larger than the sum of its proper divisors (1).

45551981 is an equidigital number, since it uses as much as digits as its factorization.

45551981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36000, while the sum is 38.

The square root of 45551981 is about 6749.2207698371. The cubic root of 45551981 is about 357.1377483688.

The spelling of 45551981 in words is "forty-five million, five hundred fifty-one thousand, nine hundred eighty-one".