1651566251 has 2 divisors, whose sum is σ = 1651566252. Its totient is φ = 1651566250.

The previous prime is 1651566247. The next prime is 1651566263. The reversal of 1651566251 is 1526651561.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1651566251 - 2² = 1651566247 is a prime.

It is not a weakly prime, because it can be changed into another prime (1651569251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 825783125 + 825783126.

It is an arithmetic number, because the mean of its divisors is an integer number (825783126).

Almost surely, 2^1651566251 is an apocalyptic number.

1651566251 is a deficient number, since it is larger than the sum of its proper divisors (1).

1651566251 is an equidigital number, since it uses as much as digits as its factorization.

1651566251 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54000, while the sum is 38.

The square root of 1651566251 is about 40639.4666672682. The cubic root of 1651566251 is about 1182.0395282164.

The spelling of 1651566251 in words is "one billion, six hundred fifty-one million, five hundred sixty-six thousand, two hundred fifty-one".