7721698123981 has 16 divisors (see below), whose sum is σ = 7775005455360. Its totient is φ = 7668584098560.

The previous prime is 7721698123963. The next prime is 7721698123991. The reversal of 7721698123981 is 1893218961277.

It is a cyclic number.

It is not a de Polignac number, because 7721698123981 - 2²¹ = 7721696026829 is a prime.

It is a super-2 number, since 2×7721698123981² (a number of 27 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 (7721698123991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 572522220 + ... + 572535706.

It is an arithmetic number, because the mean of its divisors is an integer number (485937840960).

Almost surely, 2^{7721698123981} is an apocalyptic number.

It is an amenable number.

7721698123981 is a deficient number, since it is larger than the sum of its proper divisors (53307331379).

7721698123981 is a wasteful number, since it uses less digits than its factorization.

7721698123981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20364.

The product of its digits is 18289152, while the sum is 64.

The spelling of 7721698123981 in words is "seven trillion, seven hundred twenty-one billion, six hundred ninety-eight million, one hundred twenty-three thousand, nine hundred eighty-one".