87250721 has 4 divisors (see below), whose sum is σ = 87502512. Its totient is φ = 86998932.

The previous prime is 87250697. The next prime is 87250759. The reversal of 87250721 is 12705278.

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: 12705278 = 2 ⋅6352639.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87250721 is a prime.

It is a super-2 number, since 2×87250721² = 15225376630039682, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87250021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125375 + ... + 126068.

It is an arithmetic number, because the mean of its divisors is an integer number (21875628).

Almost surely, 2^87250721 is an apocalyptic number.

It is an amenable number.

87250721 is a deficient number, since it is larger than the sum of its proper divisors (251791).

87250721 is a wasteful number, since it uses less digits than its factorization.

87250721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251790.

The product of its (nonzero) digits is 7840, while the sum is 32.

The square root of 87250721 is about 9340.8094403001. The cubic root of 87250721 is about 443.5300078369.

Adding to 87250721 its reverse (12705278), we get a palindrome (99955999).

The spelling of 87250721 in words is "eighty-seven million, two hundred fifty thousand, seven hundred twenty-one".