1401251821 has 2 divisors, whose sum is σ = 1401251822. Its totient is φ = 1401251820.

The previous prime is 1401251807. The next prime is 1401251837. The reversal of 1401251821 is 1281521041.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 853457796 + 547794025 = 29214^2 + 23405^2 .

It is a cyclic number.

It is not a de Polignac number, because 1401251821 - 2⁷ = 1401251693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1401251221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 700625910 + 700625911.

It is an arithmetic number, because the mean of its divisors is an integer number (700625911).

Almost surely, 2^1401251821 is an apocalyptic number.

It is an amenable number.

1401251821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1401251821 is an equidigital number, since it uses as much as digits as its factorization.

1401251821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 1401251821 is about 37433.2982917616. The cubic root of 1401251821 is about 1119.0222709207.

Adding to 1401251821 its reverse (1281521041), we get a palindrome (2682772862).

The spelling of 1401251821 in words is "one billion, four hundred one million, two hundred fifty-one thousand, eight hundred twenty-one".