1777216421 has 4 divisors (see below), whose sum is σ = 1779151200. Its totient is φ = 1775281644.

The previous prime is 1777216411. The next prime is 1777216447. The reversal of 1777216421 is 1246127771.

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 1777216421 - 2²⁶ = 1710107557 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 (1777216411) 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, 966011 + ... + 967848.

It is an arithmetic number, because the mean of its divisors is an integer number (444787800).

Almost surely, 2^1777216421 is an apocalyptic number.

It is an amenable number.

1777216421 is a deficient number, since it is larger than the sum of its proper divisors (1934779).

1777216421 is an equidigital number, since it uses as much as digits as its factorization.

1777216421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1934778.

The product of its digits is 32928, while the sum is 38.

The square root of 1777216421 is about 42157.0447375050. The cubic root of 1777216421 is about 1211.2862085117.

The spelling of 1777216421 in words is "one billion, seven hundred seventy-seven million, two hundred sixteen thousand, four hundred twenty-one".