1640621111 has 2 divisors, whose sum is σ = 1640621112. Its totient is φ = 1640621110.

The previous prime is 1640621071. The next prime is 1640621149. The reversal of 1640621111 is 1111260461.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1640621111 - 2¹⁴ = 1640604727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1640671111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820310555 + 820310556.

It is an arithmetic number, because the mean of its divisors is an integer number (820310556).

Almost surely, 2^1640621111 is an apocalyptic number.

1640621111 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640621111 is an equidigital number, since it uses as much as digits as its factorization.

1640621111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 1640621111 is about 40504.5813581624. The cubic root of 1640621111 is about 1179.4225631616.

Adding to 1640621111 its reverse (1111260461), we get a palindrome (2751881572).

The spelling of 1640621111 in words is "one billion, six hundred forty million, six hundred twenty-one thousand, one hundred eleven".