126821015681661 has 48 divisors (see below), whose sum is σ = 209441554882560. Its totient is φ = 72439310288160.

The previous prime is 126821015681623. The next prime is 126821015681699. The reversal of 126821015681661 is 166186510128621.

It is a happy number.

126821015681661 is a `hidden beast` number, since 1 + 2 + 6 + 8 + 2 + 1 + 0 + 1 + 568 + 16 + 61 = 666.

It is an interprime number because it is at equal distance from previous prime (126821015681623) and next prime (126821015681699).

It is not a de Polignac number, because 126821015681661 - 2²¹ = 126821013584509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 126821015681598 and 126821015681607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126821015682661) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1605716670 + ... + 1605795648.

It is an arithmetic number, because the mean of its divisors is an integer number (4363365726720).

Almost surely, 2^{126821015681661} is an apocalyptic number.

It is an amenable number.

126821015681661 is a deficient number, since it is larger than the sum of its proper divisors (82620539200899).

126821015681661 is a wasteful number, since it uses less digits than its factorization.

126821015681661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89166 (or 89163 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 54.

The spelling of 126821015681661 in words is "one hundred twenty-six trillion, eight hundred twenty-one billion, fifteen million, six hundred eighty-one thousand, six hundred sixty-one".