1651297261 has 4 divisors (see below), whose sum is σ = 1748432412. Its totient is φ = 1554162112.

The previous prime is 1651297253. The next prime is 1651297273. The reversal of 1651297261 is 1627921561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1458781636 + 192515625 = 38194^2 + 13875^2 .

It is a cyclic number.

It is not a de Polignac number, because 1651297261 - 2³ = 1651297253 is a prime.

It is a super-2 number, since 2×1651297261² = 5453565288372204242, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1651297061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48567550 + ... + 48567583.

It is an arithmetic number, because the mean of its divisors is an integer number (437108103).

Almost surely, 2^1651297261 is an apocalyptic number.

It is an amenable number.

1651297261 is a deficient number, since it is larger than the sum of its proper divisors (97135151).

1651297261 is an equidigital number, since it uses as much as digits as its factorization.

1651297261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97135150.

The product of its digits is 45360, while the sum is 40.

The square root of 1651297261 is about 40636.1570648604. The cubic root of 1651297261 is about 1181.9753519482.

The spelling of 1651297261 in words is "one billion, six hundred fifty-one million, two hundred ninety-seven thousand, two hundred sixty-one".