1809736681 has 9 divisors (see below), whose sum is σ = 1910852541. Its totient is φ = 1713721644.

The previous prime is 1809736633. The next prime is 1809736699. The reversal of 1809736681 is 1866379081.

The square root of 1809736681 is 42541.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 1809736681 - 2⁷ = 1809736553 is a prime.

It is a super-2 number, since 2×1809736681² = 6550293709113791522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1809706681) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 807160 + ... + 809398.

It is an arithmetic number, because the mean of its divisors is an integer number (212316949).

Almost surely, 2^1809736681 is an apocalyptic number.

1809736681 is the 42541-st square number.

1809736681 is the 21271-st centered octagonal number.

It is an amenable number.

1809736681 is a deficient number, since it is larger than the sum of its proper divisors (101115860).

1809736681 is an frugal number, since it uses more digits than its factorization.

1809736681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4516 (or 2258 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 49.

The cubic root of 1809736681 is about 1218.6298065435.

Multiplying 1809736681 by its sum of digits (49), we get a square (88677097369 = 297787²).

The spelling of 1809736681 in words is "one billion, eight hundred nine million, seven hundred thirty-six thousand, six hundred eighty-one".