51721804 has 6 divisors (see below), whose sum is σ = 90513164. Its totient is φ = 25860900.

The previous prime is 51721801. The next prime is 51721807. The reversal of 51721804 is 40812715.

It is an interprime number because it is at equal distance from previous prime (51721801) and next prime (51721807).

It is not an unprimeable number, because it can be changed into a prime (51721801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6465222 + ... + 6465229.

Almost surely, 2^51721804 is an apocalyptic number.

It is an amenable number.

51721804 is a deficient number, since it is larger than the sum of its proper divisors (38791360).

51721804 is a wasteful number, since it uses less digits than its factorization.

51721804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12930455 (or 12930453 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 51721804 is about 7191.7872604798. The cubic root of 51721804 is about 372.5843035472.

It can be divided in two parts, 51721 and 804, that added together give a palindrome (52525).

The spelling of 51721804 in words is "fifty-one million, seven hundred twenty-one thousand, eight hundred four".