7700021 has 8 divisors (see below), whose sum is σ = 8924544. Its totient is φ = 6506640.

The previous prime is 7699981. The next prime is 7700071. The reversal of 7700021 is 1200077.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-7700021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7700071) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7250 + ... + 8243.

It is an arithmetic number, because the mean of its divisors is an integer number (1115568).

Almost surely, 2^7700021 is an apocalyptic number.

7700021 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

It is an amenable number.

7700021 is a deficient number, since it is larger than the sum of its proper divisors (1224523).

7700021 is a wasteful number, since it uses less digits than its factorization.

7700021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15571.

The product of its (nonzero) digits is 98, while the sum is 17.

The square root of 7700021 is about 2774.8911690371. The cubic root of 7700021 is about 197.4682617375.

Adding to 7700021 its reverse (1200077), we get a palindrome (8900098).

The spelling of 7700021 in words is "seven million, seven hundred thousand, twenty-one".