77221407 has 4 divisors (see below), whose sum is σ = 102961880. Its totient is φ = 51480936.

The previous prime is 77221399. The next prime is 77221427. The reversal of 77221407 is 70412277.

77221407 = T₄₁₃₈ + T₄₁₃₉ + ... + T₄₁₄₆.

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

It is not a de Polignac number, because 77221407 - 2³ = 77221399 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 (77221427) 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, 12870232 + ... + 12870237.

It is an arithmetic number, because the mean of its divisors is an integer number (25740470).

Almost surely, 2^77221407 is an apocalyptic number.

77221407 is a deficient number, since it is larger than the sum of its proper divisors (25740473).

77221407 is a wasteful number, since it uses less digits than its factorization.

77221407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25740472.

The product of its (nonzero) digits is 5488, while the sum is 30.

The square root of 77221407 is about 8787.5711661414. The cubic root of 77221407 is about 425.8394609876.

The spelling of 77221407 in words is "seventy-seven million, two hundred twenty-one thousand, four hundred seven".