64401881 has 2 divisors, whose sum is σ = 64401882. Its totient is φ = 64401880.

The previous prime is 64401877. The next prime is 64401893. The reversal of 64401881 is 18810446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62552281 + 1849600 = 7909^2 + 1360^2 .

It is a cyclic number.

It is not a de Polignac number, because 64401881 - 2² = 64401877 is a prime.

It is a super-2 number, since 2×64401881² = 8295204552676322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (64401581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32200940 + 32200941.

It is an arithmetic number, because the mean of its divisors is an integer number (32200941).

Almost surely, 2^64401881 is an apocalyptic number.

It is an amenable number.

64401881 is a deficient number, since it is larger than the sum of its proper divisors (1).

64401881 is an equidigital number, since it uses as much as digits as its factorization.

64401881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6144, while the sum is 32.

The square root of 64401881 is about 8025.0782550702. The cubic root of 64401881 is about 400.8355056938.

The spelling of 64401881 in words is "sixty-four million, four hundred one thousand, eight hundred eighty-one".