697120021 has 4 divisors (see below), whose sum is σ = 750744652. Its totient is φ = 643495392.

The previous prime is 697120019. The next prime is 697120057. The reversal of 697120021 is 120021796.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 62583921 + 634536100 = 7911^2 + 25190^2 .

It is a cyclic number.

It is not a de Polignac number, because 697120021 - 2¹ = 697120019 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 (697127021) 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, 26812296 + ... + 26812321.

It is an arithmetic number, because the mean of its divisors is an integer number (187686163).

Almost surely, 2^697120021 is an apocalyptic number.

It is an amenable number.

697120021 is a deficient number, since it is larger than the sum of its proper divisors (53624631).

697120021 is a wasteful number, since it uses less digits than its factorization.

697120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53624630.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 697120021 is about 26403.0305268164. The cubic root of 697120021 is about 886.6846399175.

The spelling of 697120021 in words is "six hundred ninety-seven million, one hundred twenty thousand, twenty-one".