87981909 has 8 divisors (see below), whose sum is σ = 118722912. Its totient is φ = 57947760.

The previous prime is 87981889. The next prime is 87981931. The reversal of 87981909 is 90918978.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 87981909 - 2²⁰ = 86933333 is a prime.

It is a super-2 number, since 2×87981909² = 15481632622568562, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87981109) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176422 + ... + 176919.

It is an arithmetic number, because the mean of its divisors is an integer number (14840364).

Almost surely, 2^87981909 is an apocalyptic number.

It is an amenable number.

87981909 is a deficient number, since it is larger than the sum of its proper divisors (30741003).

87981909 is a wasteful number, since it uses less digits than its factorization.

87981909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353427.

The product of its (nonzero) digits is 326592, while the sum is 51.

The square root of 87981909 is about 9379.8672165442. The cubic root of 87981909 is about 444.7655357038.

The spelling of 87981909 in words is "eighty-seven million, nine hundred eighty-one thousand, nine hundred nine".