1001251681 has 2 divisors, whose sum is σ = 1001251682. Its totient is φ = 1001251680.

The previous prime is 1001251649. The next prime is 1001251711. The reversal of 1001251681 is 1861521001.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 702515025 + 298736656 = 26505^2 + 17284^2 .

It is a cyclic number.

It is not a de Polignac number, because 1001251681 - 2⁵ = 1001251649 is a prime.

It is a super-2 number, since 2×1001251681² = 2005009857410651522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1001257681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500625840 + 500625841.

It is an arithmetic number, because the mean of its divisors is an integer number (500625841).

Almost surely, 2^1001251681 is an apocalyptic number.

It is an amenable number.

1001251681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001251681 is an equidigital number, since it uses as much as digits as its factorization.

1001251681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 25.

The square root of 1001251681 is about 31642.5612269298. The cubic root of 1001251681 is about 1000.4170530426.

Adding to 1001251681 its reverse (1861521001), we get a palindrome (2862772682).

The spelling of 1001251681 in words is "one billion, one million, two hundred fifty-one thousand, six hundred eighty-one".