651461978 has 4 divisors (see below), whose sum is σ = 977192970. Its totient is φ = 325730988.

The previous prime is 651461977. The next prime is 651461999. The reversal of 651461978 is 879164156.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 570875449 + 80586529 = 23893^2 + 8977^2 .

It is not an unprimeable number, because it can be changed into a prime (651461977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 162865493 + ... + 162865496.

Almost surely, 2^651461978 is an apocalyptic number.

651461978 is a deficient number, since it is larger than the sum of its proper divisors (325730992).

651461978 is a wasteful number, since it uses less digits than its factorization.

651461978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325730991.

The product of its digits is 362880, while the sum is 47.

The square root of 651461978 is about 25523.7532114695. The cubic root of 651461978 is about 866.8880664801. Note that the first 3 decimals are identical.

The spelling of 651461978 in words is "six hundred fifty-one million, four hundred sixty-one thousand, nine hundred seventy-eight".