651877621 has 2 divisors, whose sum is σ = 651877622. Its totient is φ = 651877620.

The previous prime is 651877619. The next prime is 651877637. The reversal of 651877621 is 126778156.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 651780900 + 96721 = 25530^2 + 311^2 .

It is a cyclic number.

It is not a de Polignac number, because 651877621 - 2¹ = 651877619 is a prime.

Together with 651877619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (651877651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 325938810 + 325938811.

It is an arithmetic number, because the mean of its divisors is an integer number (325938811).

Almost surely, 2^651877621 is an apocalyptic number.

It is an amenable number.

651877621 is a deficient number, since it is larger than the sum of its proper divisors (1).

651877621 is an equidigital number, since it uses as much as digits as its factorization.

651877621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 141120, while the sum is 43.

The square root of 651877621 is about 25531.8941913835. The cubic root of 651877621 is about 867.0723900308.

The spelling of 651877621 in words is "six hundred fifty-one million, eight hundred seventy-seven thousand, six hundred twenty-one".