64737821 has 2 divisors, whose sum is σ = 64737822. Its totient is φ = 64737820.

The previous prime is 64737779. The next prime is 64737823. The reversal of 64737821 is 12873746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56100100 + 8637721 = 7490^2 + 2939^2 .

It is a cyclic number.

It is not a de Polignac number, because 64737821 - 2²² = 60543517 is a prime.

Together with 64737823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64737823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32368910 + 32368911.

It is an arithmetic number, because the mean of its divisors is an integer number (32368911).

Almost surely, 2^64737821 is an apocalyptic number.

It is an amenable number.

64737821 is a deficient number, since it is larger than the sum of its proper divisors (1).

64737821 is an equidigital number, since it uses as much as digits as its factorization.

64737821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56448, while the sum is 38.

The square root of 64737821 is about 8045.9816678886. The cubic root of 64737821 is about 401.5312577277.

The spelling of 64737821 in words is "sixty-four million, seven hundred thirty-seven thousand, eight hundred twenty-one".