1665211651 has 2 divisors, whose sum is σ = 1665211652. Its totient is φ = 1665211650.

The previous prime is 1665211637. The next prime is 1665211663. The reversal of 1665211651 is 1561125661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1665211651 - 2¹¹ = 1665209603 is a prime.

It is a super-2 number, since 2×1665211651² = 5545859685252291602, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1665211601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832605825 + 832605826.

It is an arithmetic number, because the mean of its divisors is an integer number (832605826).

Almost surely, 2^1665211651 is an apocalyptic number.

1665211651 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665211651 is an equidigital number, since it uses as much as digits as its factorization.

1665211651 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10800, while the sum is 34.

The square root of 1665211651 is about 40807.0049256252. The cubic root of 1665211651 is about 1185.2859786799.

The spelling of 1665211651 in words is "one billion, six hundred sixty-five million, two hundred eleven thousand, six hundred fifty-one".