51198904621 has 4 divisors (see below), whose sum is σ = 51350830492. Its totient is φ = 51046978752.

The previous prime is 51198904597. The next prime is 51198904663. The reversal of 51198904621 is 12640989115.

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 20333334025 + 30865570596 = 142595^2 + 175686^2 .

It is a cyclic number.

It is not a de Polignac number, because 51198904621 - 2¹³ = 51198896429 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 (51198902621) 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, 75962430 + ... + 75963103.

It is an arithmetic number, because the mean of its divisors is an integer number (12837707623).

Almost surely, 2^51198904621 is an apocalyptic number.

It is an amenable number.

51198904621 is a deficient number, since it is larger than the sum of its proper divisors (151925871).

51198904621 is a wasteful number, since it uses less digits than its factorization.

51198904621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151925870.

The product of its (nonzero) digits is 155520, while the sum is 46.

The spelling of 51198904621 in words is "fifty-one billion, one hundred ninety-eight million, nine hundred four thousand, six hundred twenty-one".