40728781 has 2 divisors, whose sum is σ = 40728782. Its totient is φ = 40728780.

The previous prime is 40728763. The next prime is 40728797. The reversal of 40728781 is 18782704.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34327881 + 6400900 = 5859^2 + 2530^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40728781 is a prime.

It is a super-2 number, since 2×40728781² = 3317667203491922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 40728781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40728581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20364390 + 20364391.

It is an arithmetic number, because the mean of its divisors is an integer number (20364391).

Almost surely, 2^40728781 is an apocalyptic number.

It is an amenable number.

40728781 is a deficient number, since it is larger than the sum of its proper divisors (1).

40728781 is an equidigital number, since it uses as much as digits as its factorization.

40728781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25088, while the sum is 37.

The square root of 40728781 is about 6381.9104506409. The cubic root of 40728781 is about 344.0596981529.

The spelling of 40728781 in words is "forty million, seven hundred twenty-eight thousand, seven hundred eighty-one".