87405781 has 4 divisors (see below), whose sum is σ = 87428512. Its totient is φ = 87383052.

The previous prime is 87405779. The next prime is 87405793. The reversal of 87405781 is 18750478.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18750478 = 2 ⋅9375239.

It is a cyclic number.

It is not a de Polignac number, because 87405781 - 2¹ = 87405779 is a prime.

It is a super-2 number, since 2×87405781² = 15279541104439922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87405751) 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, 4011 + ... + 13816.

It is an arithmetic number, because the mean of its divisors is an integer number (21857128).

Almost surely, 2^87405781 is an apocalyptic number.

It is an amenable number.

87405781 is a deficient number, since it is larger than the sum of its proper divisors (22731).

87405781 is a wasteful number, since it uses less digits than its factorization.

87405781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22730.

The product of its (nonzero) digits is 62720, while the sum is 40.

The square root of 87405781 is about 9349.1058930788. The cubic root of 87405781 is about 443.7925961623.

The spelling of 87405781 in words is "eighty-seven million, four hundred five thousand, seven hundred eighty-one".