81406730 has 16 divisors (see below), whose sum is σ = 150106824. Its totient is φ = 31768320.

The previous prime is 81406723. The next prime is 81406751. The reversal of 81406730 is 3760418.

It can be written as a sum of positive squares in 4 ways, for example, as 65302561 + 16104169 = 8081^2 + 4013^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81406693 and 81406702.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98867 + ... + 99686.

Almost surely, 2^81406730 is an apocalyptic number.

81406730 is a deficient number, since it is larger than the sum of its proper divisors (68700094).

81406730 is a wasteful number, since it uses less digits than its factorization.

81406730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198601.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 81406730 is about 9022.5678163148. The cubic root of 81406730 is about 433.3978674434.

The spelling of 81406730 in words is "eighty-one million, four hundred six thousand, seven hundred thirty".