1531216401 has 48 divisors (see below), whose sum is σ = 2559013632. Its totient is φ = 806192640.

The previous prime is 1531216373. The next prime is 1531216417. The reversal of 1531216401 is 1046121351.

It is a happy number.

It is not a de Polignac number, because 1531216401 - 2⁷ = 1531216273 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1531216301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 70680 + ... + 89766.

It is an arithmetic number, because the mean of its divisors is an integer number (53312784).

Almost surely, 2^1531216401 is an apocalyptic number.

1531216401 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1531216401 is a deficient number, since it is larger than the sum of its proper divisors (1027797231).

1531216401 is a wasteful number, since it uses less digits than its factorization.

1531216401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19142 (or 19131 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 1531216401 is about 39130.7602916171. The cubic root of 1531216401 is about 1152.6006426918.

Adding to 1531216401 its reverse (1046121351), we get a palindrome (2577337752).

It can be divided in two parts, 15312 and 16401, that added together give a palindrome (31713).

The spelling of 1531216401 in words is "one billion, five hundred thirty-one million, two hundred sixteen thousand, four hundred one".