87261821 has 2 divisors, whose sum is σ = 87261822. Its totient is φ = 87261820.

The previous prime is 87261787. The next prime is 87261829. The reversal of 87261821 is 12816278.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 86750596 + 511225 = 9314^2 + 715^2 .

It is a cyclic number.

It is not a de Polignac number, because 87261821 - 2¹⁸ = 86999677 is a prime.

It is a super-2 number, since 2×87261821² = 15229250808472082, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87261829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43630910 + 43630911.

It is an arithmetic number, because the mean of its divisors is an integer number (43630911).

Almost surely, 2^87261821 is an apocalyptic number.

It is an amenable number.

87261821 is a deficient number, since it is larger than the sum of its proper divisors (1).

87261821 is an equidigital number, since it uses as much as digits as its factorization.

87261821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 35.

The square root of 87261821 is about 9341.4035883265. The cubic root of 87261821 is about 443.5488156064.

The spelling of 87261821 in words is "eighty-seven million, two hundred sixty-one thousand, eight hundred twenty-one".