76977821 has 4 divisors (see below), whose sum is σ = 77262144. Its totient is φ = 76693500.

The previous prime is 76977809. The next prime is 76977851. The reversal of 76977821 is 12877967.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12877967 = 2851 ⋅4517.

It is a cyclic number.

It is not a de Polignac number, because 76977821 - 2¹⁰ = 76976797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (76977851) 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, 141755 + ... + 142296.

It is an arithmetic number, because the mean of its divisors is an integer number (19315536).

Almost surely, 2^76977821 is an apocalyptic number.

It is an amenable number.

76977821 is a deficient number, since it is larger than the sum of its proper divisors (284323).

76977821 is a wasteful number, since it uses less digits than its factorization.

76977821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284322.

The product of its digits is 296352, while the sum is 47.

The square root of 76977821 is about 8773.7005305629. The cubic root of 76977821 is about 425.3912355836.

The spelling of 76977821 in words is "seventy-six million, nine hundred seventy-seven thousand, eight hundred twenty-one".