221031987 has 8 divisors (see below), whose sum is σ = 321501120. Its totient is φ = 133958760.

The previous prime is 221031983. The next prime is 221032003. The reversal of 221031987 is 789130122.

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

It is not a de Polignac number, because 221031987 - 2² = 221031983 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 6697939 = 221031987 / (2 + 2 + 1 + 0 + 3 + 1 + 9 + 8 + 7).

It is not an unprimeable number, because it can be changed into a prime (221031983) 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, 3348937 + ... + 3349002.

It is an arithmetic number, because the mean of its divisors is an integer number (40187640).

Almost surely, 2^221031987 is an apocalyptic number.

221031987 is a deficient number, since it is larger than the sum of its proper divisors (100469133).

221031987 is a wasteful number, since it uses less digits than its factorization.

221031987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6697953.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 221031987 is about 14867.1445476258. The cubic root of 221031987 is about 604.6235273642.

It can be divided in two parts, 22103 and 1987, that added together give a triangular number (24090 = T₂₁₉).

The spelling of 221031987 in words is "two hundred twenty-one million, thirty-one thousand, nine hundred eighty-seven".