1978897158 has 48 divisors (see below), whose sum is σ = 5158033920. Its totient is φ = 535640688.

The previous prime is 1978897153. The next prime is 1978897163. The reversal of 1978897158 is 8517988791.

It is an interprime number because it is at equal distance from previous prime (1978897153) and next prime (1978897163).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a junction number, because it is equal to n+sod(n) for n = 1978897095 and 1978897104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978897153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 410910 + ... + 415697.

It is an arithmetic number, because the mean of its divisors is an integer number (107459040).

Almost surely, 2^1978897158 is an apocalyptic number.

1978897158 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1978897158 is an abundant number, since it is smaller than the sum of its proper divisors (3179136762).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1978897158 is a wasteful number, since it uses less digits than its factorization.

1978897158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 826641 (or 826638 counting only the distinct ones).

The product of its digits is 10160640, while the sum is 63.

The square root of 1978897158 is about 44484.7969310865. The cubic root of 1978897158 is about 1255.4740531734.

It can be divided in two parts, 1978897 and 158, that added together give a triangular number (1979055 = T₁₉₈₉).

The spelling of 1978897158 in words is "one billion, nine hundred seventy-eight million, eight hundred ninety-seven thousand, one hundred fifty-eight".