65721490 has 24 divisors (see below), whose sum is σ = 125672292. Its totient is φ = 24741120.

The previous prime is 65721451. The next prime is 65721493. The reversal of 65721490 is 9412756.

It can be written as a sum of positive squares in 6 ways, for example, as 31393609 + 34327881 = 5603^2 + 5859^2 .

It is a Harshad number since it is a multiple of its sum of digits (34).

It is not an unprimeable number, because it can be changed into a prime (65721493) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8481 + ... + 14260.

Almost surely, 2^65721490 is an apocalyptic number.

65721490 is a deficient number, since it is larger than the sum of its proper divisors (59950802).

65721490 is a wasteful number, since it uses less digits than its factorization.

65721490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22782 (or 22765 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 65721490 is about 8106.8791775874. The cubic root of 65721490 is about 403.5547532426.

The spelling of 65721490 in words is "sixty-five million, seven hundred twenty-one thousand, four hundred ninety".