82787921 has 4 divisors (see below), whose sum is σ = 87145200. Its totient is φ = 78430644.

The previous prime is 82787893. The next prime is 82787951. The reversal of 82787921 is 12978728.

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.

It is a cyclic number.

It is not a de Polignac number, because 82787921 - 2¹⁸ = 82525777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (82787951) 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, 2178611 + ... + 2178648.

It is an arithmetic number, because the mean of its divisors is an integer number (21786300).

Almost surely, 2^82787921 is an apocalyptic number.

It is an amenable number.

82787921 is a deficient number, since it is larger than the sum of its proper divisors (4357279).

82787921 is a wasteful number, since it uses less digits than its factorization.

82787921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4357278.

The product of its digits is 112896, while the sum is 44.

The square root of 82787921 is about 9098.7867872591. The cubic root of 82787921 is about 435.8352227125.

The spelling of 82787921 in words is "eighty-two million, seven hundred eighty-seven thousand, nine hundred twenty-one".