77450021 has 4 divisors (see below), whose sum is σ = 84490944. Its totient is φ = 70409100.

The previous prime is 77450003. The next prime is 77450029. The reversal of 77450021 is 12005477.

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 a de Polignac number, because none of the positive numbers 2^k-77450021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77450029) 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, 3520445 + ... + 3520466.

It is an arithmetic number, because the mean of its divisors is an integer number (21122736).

Almost surely, 2^77450021 is an apocalyptic number.

It is an amenable number.

77450021 is a deficient number, since it is larger than the sum of its proper divisors (7040923).

77450021 is a wasteful number, since it uses less digits than its factorization.

77450021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7040922.

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 77450021 is about 8800.5693565814. The cubic root of 77450021 is about 426.2592795886.

Adding to 77450021 its reverse (12005477), we get a palindrome (89455498).

The spelling of 77450021 in words is "seventy-seven million, four hundred fifty thousand, twenty-one".