826420721 has 12 divisors (see below), whose sum is σ = 963068580. Its totient is φ = 707091840.

The previous prime is 826420717. The next prime is 826420753. The reversal of 826420721 is 127024628.

It can be written as a sum of positive squares in 2 ways, for example, as 489294400 + 337126321 = 22120^2 + 18361^2 .

It is not a de Polignac number, because 826420721 - 2² = 826420717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (826420781) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13061 + ... + 42701.

It is an arithmetic number, because the mean of its divisors is an integer number (80255715).

Almost surely, 2^826420721 is an apocalyptic number.

It is an amenable number.

826420721 is a deficient number, since it is larger than the sum of its proper divisors (136647859).

826420721 is a wasteful number, since it uses less digits than its factorization.

826420721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30224 (or 30217 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 32.

The square root of 826420721 is about 28747.5341725164. The cubic root of 826420721 is about 938.4267939708.

The spelling of 826420721 in words is "eight hundred twenty-six million, four hundred twenty thousand, seven hundred twenty-one".