64973721 has 8 divisors (see below), whose sum is σ = 86762304. Its totient is φ = 43250480.

The previous prime is 64973669. The next prime is 64973729. The reversal of 64973721 is 12737946.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 64973721 - 2¹⁹ = 64449433 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 64973721.

It is not an unprimeable number, because it can be changed into a prime (64973729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13965 + ... + 18026.

It is an arithmetic number, because the mean of its divisors is an integer number (10845288).

Almost surely, 2^64973721 is an apocalyptic number.

It is an amenable number.

64973721 is a deficient number, since it is larger than the sum of its proper divisors (21788583).

64973721 is a wasteful number, since it uses less digits than its factorization.

64973721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32671.

The product of its digits is 63504, while the sum is 39.

The square root of 64973721 is about 8060.6278291458. The cubic root of 64973721 is about 402.0183836052.

The spelling of 64973721 in words is "sixty-four million, nine hundred seventy-three thousand, seven hundred twenty-one".