1401528721 has 2 divisors, whose sum is σ = 1401528722. Its totient is φ = 1401528720.

The previous prime is 1401528691. The next prime is 1401528731. The reversal of 1401528721 is 1278251041.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1172309121 + 229219600 = 34239^2 + 15140^2 .

It is an emirp because it is prime and its reverse (1278251041) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1401528721 - 2⁹ = 1401528209 is a prime.

It is not a weakly prime, because it can be changed into another prime (1401528731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 700764360 + 700764361.

It is an arithmetic number, because the mean of its divisors is an integer number (700764361).

Almost surely, 2^1401528721 is an apocalyptic number.

It is an amenable number.

1401528721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1401528721 is an equidigital number, since it uses as much as digits as its factorization.

1401528721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4480, while the sum is 31.

The square root of 1401528721 is about 37436.9966877686. The cubic root of 1401528721 is about 1119.0959756977.

Adding to 1401528721 its reverse (1278251041), we get a palindrome (2679779762).

The spelling of 1401528721 in words is "one billion, four hundred one million, five hundred twenty-eight thousand, seven hundred twenty-one".