61533976421 has 2 divisors, whose sum is σ = 61533976422. Its totient is φ = 61533976420.

The previous prime is 61533976409. The next prime is 61533976429. The reversal of 61533976421 is 12467933516.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59316602500 + 2217373921 = 243550^2 + 47089^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61533976421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61533976429) 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 as a sum of consecutive naturals, namely, 30766988210 + 30766988211.

It is an arithmetic number, because the mean of its divisors is an integer number (30766988211).

Almost surely, 2^61533976421 is an apocalyptic number.

It is an amenable number.

61533976421 is a deficient number, since it is larger than the sum of its proper divisors (1).

61533976421 is an equidigital number, since it uses as much as digits as its factorization.

61533976421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 816480, while the sum is 47.

The spelling of 61533976421 in words is "sixty-one billion, five hundred thirty-three million, nine hundred seventy-six thousand, four hundred twenty-one".