81403737849604 has 81 divisors (see below), whose sum is σ = 148432062839221. Its totient is φ = 39062669907040.

The previous prime is 81403737849601. The next prime is 81403737849641. The reversal of 81403737849604 is 40694873730418.

The square root of 81403737849604 is 9022402.

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

It can be written as a sum of positive squares in only one way, i.e., 58683719880900 + 22720017968704 = 7660530^2 + 4766552^2 .

It is a Smith number, since the sum of its digits (64) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81403737849601) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 44949605859 + ... + 44949607669.

Almost surely, 2^{81403737849604} is an apocalyptic number.

81403737849604 is the 9022402-nd square number.

It is an amenable number.

81403737849604 is a deficient number, since it is larger than the sum of its proper divisors (67028324989617).

81403737849604 is an frugal number, since it uses more digits than its factorization.

81403737849604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3826 (or 1913 counting only the distinct ones).

The product of its (nonzero) digits is 97542144, while the sum is 64.

The spelling of 81403737849604 in words is "eighty-one trillion, four hundred three billion, seven hundred thirty-seven million, eight hundred forty-nine thousand, six hundred four".