40651921 has 2 divisors, whose sum is σ = 40651922. Its totient is φ = 40651920.

The previous prime is 40651889. The next prime is 40651927. The reversal of 40651921 is 12915604.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37638225 + 3013696 = 6135^2 + 1736^2 .

It is a cyclic number.

It is not a de Polignac number, because 40651921 - 2⁵ = 40651889 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 40651921.

It is not a weakly prime, because it can be changed into another prime (40651927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20325960 + 20325961.

It is an arithmetic number, because the mean of its divisors is an integer number (20325961).

Almost surely, 2^40651921 is an apocalyptic number.

It is an amenable number.

40651921 is a deficient number, since it is larger than the sum of its proper divisors (1).

40651921 is an equidigital number, since it uses as much as digits as its factorization.

40651921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 40651921 is about 6375.8858992300. The cubic root of 40651921 is about 343.8431348301.

The spelling of 40651921 in words is "forty million, six hundred fifty-one thousand, nine hundred twenty-one".