1531947681 has 16 divisors (see below), whose sum is σ = 2475875520. Its totient is φ = 928452960.

The previous prime is 1531947679. The next prime is 1531947701. The reversal of 1531947681 is 1867491351.

It is not a de Polignac number, because 1531947681 - 2¹ = 1531947679 is a prime.

It is a super-2 number, since 2×1531947681² = 4693727394642555522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1531947611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2578740 + ... + 2579333.

It is an arithmetic number, because the mean of its divisors is an integer number (154742220).

Almost surely, 2^1531947681 is an apocalyptic number.

1531947681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1531947681 is a deficient number, since it is larger than the sum of its proper divisors (943927839).

1531947681 is a wasteful number, since it uses less digits than its factorization.

1531947681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5158093 (or 5158087 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 1531947681 is about 39140.1032318516. The cubic root of 1531947681 is about 1152.7841002472.

The spelling of 1531947681 in words is "one billion, five hundred thirty-one million, nine hundred forty-seven thousand, six hundred eighty-one".