698181621021 has 6 divisors (see below), whose sum is σ = 1008484563710. Its totient is φ = 465454414008.

The previous prime is 698181621013. The next prime is 698181621047. The reversal of 698181621021 is 120126181896.

It is a happy number.

698181621021 is a `hidden beast` number, since 6 + 9 + 8 + 18 + 1 + 621 + 0 + 2 + 1 = 666.

698181621021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 540723444921 + 157458176100 = 735339^2 + 396810^2 .

It is not a de Polignac number, because 698181621021 - 2³ = 698181621013 is a prime.

It is a super-2 number, since 2×698181621021² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (698181621721) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 38787867826 + ... + 38787867843.

Almost surely, 2^698181621021 is an apocalyptic number.

It is an amenable number.

698181621021 is a deficient number, since it is larger than the sum of its proper divisors (310302942689).

698181621021 is a wasteful number, since it uses less digits than its factorization.

698181621021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77575735675 (or 77575735672 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 45.

The spelling of 698181621021 in words is "six hundred ninety-eight billion, one hundred eighty-one million, six hundred twenty-one thousand, twenty-one".