20191487 has 4 divisors (see below), whose sum is σ = 20376840. Its totient is φ = 20006136.

The previous prime is 20191481. The next prime is 20191489. The reversal of 20191487 is 78419102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20191487 - 2⁸ = 20191231 is a prime.

It is a super-2 number, since 2×20191487² = 815392294542338, 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 (20191481) 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, 92513 + ... + 92730.

It is an arithmetic number, because the mean of its divisors is an integer number (5094210).

Almost surely, 2^20191487 is an apocalyptic number.

20191487 is a deficient number, since it is larger than the sum of its proper divisors (185353).

20191487 is a wasteful number, since it uses less digits than its factorization.

20191487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185352.

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 20191487 is about 4493.4938522268. The cubic root of 20191487 is about 272.3053043522.

The spelling of 20191487 in words is "twenty million, one hundred ninety-one thousand, four hundred eighty-seven".