78914990994921 has 9 divisors (see below), whose sum is σ = 113988358820791. Its totient is φ = 52609976229792.

The previous prime is 78914990994799. The next prime is 78914990994941. The reversal of 78914990994921 is 12949909941987.

It is a happy number.

The square root of 78914990994921 is 8883411.

It is a perfect power (a square), and thus also a powerful number.

78914990994921 is a `hidden beast` number, since 7 + 89 + 1 + 49 + 9 + 0 + 9 + 9 + 492 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 48175329314025 + 30739661680896 = 6940845^2 + 5544336^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 78914990994921 - 2¹⁵ = 78914990962153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78914990994941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 25169665 + ... + 28130801.

Almost surely, 2^{78914990994921} is an apocalyptic number.

78914990994921 is the 8883411-st square number.

78914990994921 is the 4441706-th centered octagonal number.

It is an amenable number.

78914990994921 is a deficient number, since it is larger than the sum of its proper divisors (35073367825870).

78914990994921 is an frugal number, since it uses more digits than its factorization.

78914990994921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5922280 (or 2961140 counting only the distinct ones).

The product of its (nonzero) digits is 952342272, while the sum is 81.

The spelling of 78914990994921 in words is "seventy-eight trillion, nine hundred fourteen billion, nine hundred ninety million, nine hundred ninety-four thousand, nine hundred twenty-one".