81627421 has 4 divisors (see below), whose sum is σ = 86429052. Its totient is φ = 76825792.

The previous prime is 81627419. The next prime is 81627449. The reversal of 81627421 is 12472618.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12472618 = 2 ⋅6236309.

It can be written as a sum of positive squares in 2 ways, for example, as 50211396 + 31416025 = 7086^2 + 5605^2 .

It is a cyclic number.

It is not a de Polignac number, because 81627421 - 2¹ = 81627419 is a prime.

It is a super-2 number, since 2×81627421² = 13326071718222482, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81627451) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2400790 + ... + 2400823.

It is an arithmetic number, because the mean of its divisors is an integer number (21607263).

Almost surely, 2^81627421 is an apocalyptic number.

It is an amenable number.

81627421 is a deficient number, since it is larger than the sum of its proper divisors (4801631).

81627421 is a wasteful number, since it uses less digits than its factorization.

81627421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4801630.

The product of its digits is 5376, while the sum is 31.

The square root of 81627421 is about 9034.7894828823. The cubic root of 81627421 is about 433.7891565777.

The spelling of 81627421 in words is "eighty-one million, six hundred twenty-seven thousand, four hundred twenty-one".