64451621 has 4 divisors (see below), whose sum is σ = 69409452. Its totient is φ = 59493792.

The previous prime is 64451567. The next prime is 64451633. The reversal of 64451621 is 12615446.

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 39551521 + 24900100 = 6289^2 + 4990^2 .

It is a cyclic number.

It is not a de Polignac number, because 64451621 - 2¹⁴ = 64435237 is a prime.

It is a super-2 number, since 2×64451621² = 8308022899055282, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64451671) 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, 2478896 + ... + 2478921.

It is an arithmetic number, because the mean of its divisors is an integer number (17352363).

Almost surely, 2^64451621 is an apocalyptic number.

It is an amenable number.

64451621 is a deficient number, since it is larger than the sum of its proper divisors (4957831).

64451621 is a wasteful number, since it uses less digits than its factorization.

64451621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4957830.

The product of its digits is 5760, while the sum is 29.

The square root of 64451621 is about 8028.1766921263. The cubic root of 64451621 is about 400.9386725947.

The spelling of 64451621 in words is "sixty-four million, four hundred fifty-one thousand, six hundred twenty-one".