21261974 has 4 divisors (see below), whose sum is σ = 31892964. Its totient is φ = 10630986.

The previous prime is 21261973. The next prime is 21261979. The reversal of 21261974 is 47916212.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21261974.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5315492 + ... + 5315495.

It is an arithmetic number, because the mean of its divisors is an integer number (7973241).

Almost surely, 2^21261974 is an apocalyptic number.

21261974 is a deficient number, since it is larger than the sum of its proper divisors (10630990).

21261974 is a wasteful number, since it uses less digits than its factorization.

21261974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10630989.

The product of its digits is 6048, while the sum is 32.

The square root of 21261974 is about 4611.0708083915. The cubic root of 21261974 is about 277.0349280635.

The spelling of 21261974 in words is "twenty-one million, two hundred sixty-one thousand, nine hundred seventy-four".