26691978 has 16 divisors (see below), whose sum is σ = 53434656. Its totient is φ = 8888880.

The previous prime is 26691947. The next prime is 26691991. The reversal of 26691978 is 87919662.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10908 + ... + 13128.

It is an arithmetic number, because the mean of its divisors is an integer number (3339666).

Almost surely, 2^26691978 is an apocalyptic number.

26691978 is an abundant number, since it is smaller than the sum of its proper divisors (26742678).

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

26691978 is a wasteful number, since it uses less digits than its factorization.

26691978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4229.

The product of its digits is 326592, while the sum is 48.

The square root of 26691978 is about 5166.4279729809. The cubic root of 26691978 is about 298.8548118203.

It can be divided in two parts, 2669197 and 8, that added together give a triangular number (2669205 = T₂₃₁₀).

The spelling of 26691978 in words is "twenty-six million, six hundred ninety-one thousand, nine hundred seventy-eight".