36821721 has 4 divisors (see below), whose sum is σ = 49095632. Its totient is φ = 24547812.

The previous prime is 36821713. The next prime is 36821737. The reversal of 36821721 is 12712863.

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: 12712863 = 3 ⋅4237621.

It is not a de Polignac number, because 36821721 - 2³ = 36821713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (36821921) 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, 6136951 + ... + 6136956.

It is an arithmetic number, because the mean of its divisors is an integer number (12273908).

Almost surely, 2^36821721 is an apocalyptic number.

It is an amenable number.

36821721 is a deficient number, since it is larger than the sum of its proper divisors (12273911).

36821721 is a wasteful number, since it uses less digits than its factorization.

36821721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12273910.

The product of its digits is 4032, while the sum is 30.

The square root of 36821721 is about 6068.0903915482. The cubic root of 36821721 is about 332.6861294168.

The spelling of 36821721 in words is "thirty-six million, eight hundred twenty-one thousand, seven hundred twenty-one".