66702021 has 4 divisors (see below), whose sum is σ = 88936032. Its totient is φ = 44468012.

The previous prime is 66702017. The next prime is 66702061. The reversal of 66702021 is 12020766.

It is a happy number.

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 66702021 - 2² = 66702017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66701982 and 66702000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66702061) 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, 11117001 + ... + 11117006.

It is an arithmetic number, because the mean of its divisors is an integer number (22234008).

Almost surely, 2^66702021 is an apocalyptic number.

It is an amenable number.

66702021 is a deficient number, since it is larger than the sum of its proper divisors (22234011).

66702021 is a wasteful number, since it uses less digits than its factorization.

66702021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22234010.

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 66702021 is about 8167.1305242417. The cubic root of 66702021 is about 405.5517977703.

Adding to 66702021 its reverse (12020766), we get a palindrome (78722787).

The spelling of 66702021 in words is "sixty-six million, seven hundred two thousand, twenty-one".